Develop Reference

ADB No Devices Found

I am attempting to install an Android app on my brand new Nexus 10. I have a .apk file. I have downloaded the Android SDK, installed "Android SDK Tools", "Android SDK Platform-tools", and Google USB Driver. I have checked the setting on my Nexus 10 for "Unknown Sources".
When I run "adb devices" from the command terminal, it doesn't list any devices. I attempted to follow this recommendation, because it was identical to a suggestion I had previously found here on Stack Overflow. After following those steps, "adb devices" still returns an empty list and to make it worse, when I connect my Nexus 10 to my PC, Windows doesn't show any folders within the device.
I have undone the steps in that link, along with everything else I have done so far, as well as uninstalling my Nexus 10 from Device Manager and reinstalling it, but I am still not seeing any folders in the device.
Is there anything I am missing to get my device to show up in ADB devices?
What can I do to get Windows to see the folders within the device?

Windows 8 wouldn't recognize my Nexus 10 device. Fixed by Setting the transfer mode to Camera (PTP) through the settings dialogue on the device.
Settings > Storage > Menu > USB Computer connection to "Camera (PTP)"

For Windows 8 users:
After trying every solution given here, with no success, I found this:
Go to Device Manager
Browse my computer for drivers -> Let me pick from a list of device drivers on my computer
Choose Android Device and then Android ADB Interface.
Now I have my devices listed at adb devices.

This situation seems to arise with some ADB drivers. I have encountered the same thing with a couple of Google devices and installing the Universal ADB windows driver has fixed it for me every time.

Use another cable.
Just found out that one of my regular charging cables had Vcc, Gnd pairs, but no Data+, Data-.
https://en.wikipedia.org/wiki/USB#Pinouts

Make sure to Enable USB debugging in Settings -> Developer options
Also, run "adb devices" after getting into the platform tools folder in the Android SDK (unless you have that folder on your system path already), otherwise the command won't be found.

The device may not be visible for debugging if it is in MTP mode. Some devices only work in PTP mode (or even in "charging only" mode).
This can be changed in Settings > Developer Options > Networking > Default USB configuration > PTP.
Also, you'll get a notification on your android device asking you for confirmation about USB configuration setting change and to allow it.
Note: You can turn on developer options by following the link below:
enable developer options

I have found a solution (for Windows 7):
Connect your Nexus 10 to PC
Go to Windows Device Manager
RClick on ADB Interface -> properties
Details -> Hardware Ids.
You will see two records like these:
USB\VID_18D1&PID_4EE2
USB\VID_18D1&PID_4EE2&MI_01
5 Open the android_winusb.inf file (I have it in "C:\Users\<username>\AppData\Local\Android\android-sdk\extras\google\usb_driver" directory)
6 Create such records in [Google.NTx86] and [Google.NTamd64] sections using Hardware Ids from properties of ADB interface:
;Google Nexus 10
%SingleAdbInterface% = USB_Install, USB\VID_18D1&PID_4EE2
%CompositeAdbInterface% = USB_Install, USB\VID_18D1&PID_4EE2&MI_01
7 Save the file, and update driver for ADB Interface with showing the path to "C:\Users\\AppData\Local\Android\android-sdk\extras\google\usb_driver" directory

Sometimes ADB loses connection to the device, and needs to be reset. If you have everything else working (ie USB driver installed, Developer settings enabled on the device), and still can't see your device, you need to reset the ADB process.
This is available in the DDMS Perspective (from within Eclipse), Devices tab (the triangle on the far right includes a menu item to perform the reset).
Otherwise from the command line, you can reset it with the following 2 commands:
adb kill-server
then
adb start-server

Enable Developer options in your device. To enable the developer mode, setting->About phone, tap Build number option 8 times continuously
Go to Settings-> Developer options and Turn on USB debugging
From the above steps it didn't work try this step, Go to Settings->Security and turn on Allow Unknown Resources

You have to download the drivers from the SDK manager (extras → Google USB Driver)
Then you have to install the USB driver in Windows (it works for me in Windows 8.1):
(Copy and paste from http://developer.android.com/tools/extras/oem-usb.html#InstallingDriver:)
Connect your Android-powered device to your computer's USB port.
Right-click on "Computer" from your desktop or Windows Explorer, and select "Manage".
Select "Devices" in the left pane.
Locate and expand "Other device" in the right pane.
Right-click the device name (such as Nexus S) and select "Update Driver Software." This will launch the "Hardware Update Wizard".
Select "Browse my computer for driver software" and click "Next."
Click "Browse" and locate the USB driver folder. (The Google USB Driver is located in <sdk>\extras\google\usb_driver\.)
Click "Next" to install the driver.

After downloading the Google drivers via Android SDK Manager (available via Eclipse, Intellij or Android Studio), I had to update the driver in Computer Management > Device Manager > Other Devices > ADB - right clicking and clicking on update driver and browsing for updated driver finally did the trick.
BTW, a total nightmare for me as well. I continue to be bewildered that setting up a dev environment should be the most difficult task imaginable, with each new inexplicable failure leading to another one. Jeesh! Good luck.

On my Windows 8.1 64bit (Nexus 5 did not show up), only manually installing the USB driver fixed it:
http://developer.android.com/sdk/win-usb.html
The "Google USB Driver" in "Android SDK Manager" was installed already.

I still get this once in a while and it usually works if I unplug it and plug it back in a different port. I'm on Linux but had the same thing happen on Windows before.

Installing Samsung Kies and using their tool to reinstall device drivers, is what finally worked for me with my Galaxy S3 and Tab S 8.4

Normally SDB will download the driver in the **android-sdk-windows\extras\google\usb_driver** path
Here are the steps that worked for me:
Enable USB debugging.
Do to device manager, right click on ADB device and click update driver software.
Select "Browse my computer for Driver Software"
Select "Let me pick from list of Device drivers on my computer"
Click on "Have Disk" option.
Select the driver path **android-sdk-windows\extras\google\usb_driver** (path of sdk)
7.Select 1st driver out of list of drivers shown.
And hopefully, it will work.

Edit: I recommend you DO NOT run ADB under VirtualBox if you are using a Windows Host. Somehow I got VirtualBox to lock the device drivers on the host, eventually making it so that the ADB wouldn't work on the client nor the host for any device I plugged in. To fix, I removed VirtualBox extensions on the host and ran http://www.nirsoft.net/utils/usb_devices_view.html to delete the incorrect drivers. I could not get the correct drivers to load while VirtualBox extensions were installed, and this problem was a complete bastard to diagnose and fix.
Edit 2: Also the following is probably out of date, now that Google have released an integrated ADB extension for Chrome.
What an installation nightmare... Here are the steps I needed to get my Nexus 10 recognised on an XP virtual machine running under VirtualBox:
If you get asked to install Nexus 10 drivers, make sure to untick "don't ask again" (you WANT to be asked again!).
Plug in the Nexus 10 USB connection
Turn on debugging in the Nexus 10 settings Developer menu (tap "About Tablet" 7 times to get that menu).
In your virtual machine settings (host), add the samsung Nexus 10 device to the USB Device Filters (important - selecting it from the devices menu didn't seem to work).
In guest install java jre (if you don't have java installed). In Control Panel, change Java settings so that java doesn't run in the browser (to help prevent security issues).
In guest get the adk zip file and put it somewhere permanent. I needed to delete the .android config directory from the user directory because I moved the directory.
Run the SDK Manager.exe - if it doesn't work, try running sdk\tools\android.bat which seems to give better error reporting.
From SDK Manager install the Google USB driver package.
Unplug the Nexus 10 and plug it in again, and install the Google USB driver package.
Restart the guest.
running c:>[...]\sdk\platformtools> adb devices finally shows me the device...

For the Blu Studio 5.5s ADB drivers, you have to go through this hoop. I am certain it is the same with all Blu phones or maybe for all non-Google mfg phones, I am not sure. First of all if you connect the Blu device with USB cable and USB Debuggin off, you will see that Windows 7 loads a generic driver for you to copy on/off files to the phone and SD storage. This will appear when the USB cable is first plugged in and appears as a device icon under Control Panel, Device Manager, Portable Devices, BLU STUDIO 5.5 S (or the device you are working with). Do not bother getting the hardware ID yet - just observe that this happens (which indicates you are good so far and don't have a bad cable or something).
Go to the phone and switch on USB Debugging in the Developer section of your phone. Notice that an additional item appears as an undefined device now in the device manager list, it will have the yellow exclamation mark and it may have the same name of the phone listed as you saw under Portable Devices. Ignore this item for the moment. Now, without doing anything to the phone (it should be already in USB debug mode) go back to the Portable Devices in Device Manager and right-click the BLU STUDIO 5.5 S or whatever phone you are working with that is listed there without the exclamation mark (listed under Portable Devices). Right click on the icon under Portable Devices, in this example the name that appears is BLU STUDIO 5.5 S. On that icon select Properties, Details, and under the pull down, select Hardware IDs and copy down what you see.
For BLU STUDIO 5.5 S I get:
USB\VID_0BB4&PID_0C02&REV_0216&MI_00
USB\VID_0BB4&PID_0C02&MI_00
(Note if you do this out of turn, the HW ID will be different with the phone USB debugging turned off. You want to copy the value that it changes to when the USB debugging is ON)
Now do as the instructions say above, of course customizing the lines you add the the INF file with those relating to your own phone, not the Nexus 10. Here is what to customize; when you downloaded the SDK you should have a file structure expanded from the ZIP such as this:
\adt-bundle-windows-x86_64-20140321\sdk\extras\google\usb_driver
Find the file named: android_winusb.inf in the usb_driver folder
Make a copy of it and name it anything, such as myname.inf
Edit the myname.inf and add the lines as instructed above only modified for your particular phone. For example, for the BLU STUDIO 5.5 S, I added the following 2 lines as instructed in the 2 locations as instructed.
;BLU STUDIO 5.5 S
%SingleAdbInterface% = USB_Install, USB\VID_0BB4&PID_0C02&REV_0216&MI_00
%CompositeAdbInterface% = USB_Install, USB\VID_0BB4&PID_0C02&MI_00
Note that you add these lines to both the 32 and 64 bit sections, matching how the example in the tutorial reads.
Now go back up to the unknown device that appeared in Device Manager when you switched on device USB debugging and right click on this item (has yellow exclamation mark), right click on it and then select Update Driver Software, and then Browse My Computer, Let Me Pick, click on the Have Disk button and browse to find the myname.inf. Continue to agree to all the prompts warning you it might not be the right driver. As the final step, Windows should have identified the device as Android ADB Interface and once that is done, you should be able to go back, open your CMD window and run the command "adb devices" as instructed in this tutorial and now you should see that the phone is now discovered and communicating.
Now you can go have fun with the adb command.

At first Thanks #rmsyk's post.
For my issue and after long time suffering with Meizu C9 Pro witch require just android ADB drivers (no special drivers) referring to manufacturer and it solved in my Windows 7 PC by the bellow steps.
Make Sure to
Install latest version of ADB & Fastboot with the needed drivers.
Enable Developer options & USB Debugging.
Enable Media File Transfer (MTP Mode).
Manually replace C:\Users\USERNAME\.android with the folder included here ,Then kill process 'adb.exe' if found from Windows Task Manager and use adb devices and finally my device listed successfully and just confirm the PC as trusted.
Notes:
Android Studio was uninstalled in earlier time and also i tried to reinstall but was not a solution at all.
Tried adb kill-server & adb start-server but was not a solution too.

As well as the usual settings (enable USB debugging) I also had to select Enable OEM unlock in the Developer options.
This supposedly makes the device less secure, but it's your device and you know what you want to do.
Once checked the device behaved as expected and appears in the adb devices list.
You can always reverse all these settings once you're finished.

Confirm you have the correct platform SDK tools
For Windows 10, had to manually download the latest platform SDK tools from Android as the version supplied through Visual Studio 2017 EMDK for Xamarin was not sufficient. Everything else except adb.exe devices worked.
https://developer.android.com/studio/releases/platform-tools
After the platform tools were manually downloaded, device showed up regardless of USB configuration (charging, MTP, etc.)
Installing an emulator device at this stage is also helpful to see whether the problem is with adb or your physical device.
List of devices attached
12345D1234 device
emulator-5554 device

There could be two reasons why adb devices command is not working for you. Either your phones USB drivers are not installed properly or you have not enabled USB debugging mode.
I created a tool that makes installing USB drivers a one click thing.
Just connect your phone in USB debugging mode to PC.
Run my tool
It will detect and install drivers specific to your phone and also install the latest ADB & Fastboot binaries with it.
The tool is available at my GitHub Repo

It's so easy, just turn off your Android device, and then hold down both "Volume Down" key and "Power" at the same time. Wait a few seconds till it start in recovery mode, done.
Now type adb devices, and you'll see your device.

I had the same problem with my Windows 8. The Android/SDK USB driver was installed correctly, but I forgot to install the USB driver from my phone. After installing the phone USB driver ADB works fine.
I hope this will help.

Turn on debugging in the Nexus settings Developer menu (tap "About Tablet" 7 times to get that menu).
Freaking Google tricks!

Have you had an android update recently? I updated to Lollipop and all the sudden I had no adb devices. Boo! I spent awhile trying a few things to no avail. Then I went into my developer options and lo and behold, "USB debugging" had been turned off. Silly Google. After turning it back on, it immediately showed up and I'm back in business!

GoTo DeviceManager, then right click on the android device and click uninstall driver.
Unplug and plug the device back...then a pop will come on your device while your pc installs the required drivers. Click "allow" on the popup.
You can see your device when you type "adb devices" in command prompt.

For Windows, just end all the processes related to Blue stacks or any such emulator if you are using.
Worked for me.

There's obviously a ton of different problems that could be causing this (and a ton of different solutions to go along with those problems). So think about all the solutions!
If you've gotten this phone and computer pair to work together before, but they aren't working any more, it might be a specific program on your computer rather than a problem on your phone. Some programs install/use their own adb, and only one of these can connect to your phone at a time. I think this makes a race condition, so sometimes it'll connect fine.
Some programs that run adb:
HTC Sync Manager - uninstall this.
chrome://inspect - lets you view localhost on your phone. Just close the window when you're done with it.

To have ADB in MTP mode
If you don't find any ADB device (nothing with exclamation mark) in the device manager (with all developers settings on phone checked), do this:
In Device Manager :
UpdateDriver->Manuel Install->Search on my computer->Select from installed driver list -> then select the one with the word usb in it (not MTP).
Edit: after that, you'll then have 2 or 3 peripheral, one for USB and one for ADB, install adb driver using usual method (see first answers)

For my Nexus 6P downloading drivers from Google helped resolved the issue. Here is the URL with documentation. And here you can download the driver itself.
P.S. I saw some people advice to download some drivers from random places on internet. While this might help it's too dangerous in my mind to download unknown drivers from unofficial places. So the one from Google worked well for me :)

Android 4.2.2 adb can't find devices

With the new update to 4.2.2 to my Galaxy Nexus and Nexus 7, I can't find both my devices under adb.
These are the steps I took:
Updated to 4.2.2
Updated ADT and SDK through the SDK Manager
Checked ADB version, it's at 1.0.31
Restarted PC and Tablet and Phone numerous times
When I run adb devices, it's just blank. I have the same issue on Windows 8 and on Ubuntu 12.10, but on Ubuntu it shows my device and it says offline.
Are there any other steps I can take?

From the adb docs
When you connect a device running Android 4.2.2 or higher to your
computer, the system shows a dialog asking whether to accept an RSA
key that allows debugging through this computer. This security
mechanism protects user devices because it ensures that USB debugging
and other adb commands cannot be executed unless you're able to unlock
the device and acknowledge the dialog. This requires that you have adb
version 1.0.31 (available with SDK Platform-tools r16.0.1 and higher)
in order to debug on a device running Android 4.2.2 or higher
So, unplug, wait, replug in the cable, and hit ok (on modal dialog that appears on your device)
If you hit cancel, the device will show up as offline via adb devices

Try pre-installing the drivers for your devices. Make sure, under Windows, that your device is recognized in the System control panel first.
I use Windows 7 and my Galaxy Nexus wouldn't be recognized by the system until I installed the device drivers before plugging them in. From the comments, this works on Windows 8 as well.
Galaxy Nexus drivers
http://www.samsung.com/us/support/owners/product/SCH-I515MSAVZW#
Goto Manual & Drivers > Software
Nexus 7
http://support.asus.com/Download.aspx?SLanguage=en&m=Nexus+7&p=28&s=2

Just though Id share my experience, I had -
Unplugged and re plugged in the device
Installed the correct platform tools
Installed the correct Android bridge Turned USB debugging on and off
and on and off an...
Tried WiFi but it said it was offline
etc. etc.
What fixed it for me was changing the device connection from Mass Storage to MTP. To do so, with the phone unplugged you go into -
"Settings" -> "Storage" -> Click the menu Button -> "USB computer
connection" -> "Media device (MTP)"
Hope this helps some one from going crazy!
Thanks,
Ash.

I tried everything mentioned here and in other posts. It wasn't the cable, the USB port, rebooting the PC or Nexus 7, killing and starting adb or enabling/disabling USB Debugging.
It was due to the 4.2.2 OTA update, I simply replaced the \platform-tools\ folder, as described here: Android ADB device offline, can't issue commands
Download the updated platform-tools: http://dl.google.com/android/repository/platform-tools_r16.0.1-windows.zip

adb wait-for-device
works for me. Just unplug your usb device, run this command, and while it's waiting, plug your device in, then it will just work. :)

Here is what I did (Galaxy S4 4.2.2):
go to Settings => about this device => click several times on "Version number", that is to say something like "JDQ39.I9505XXBHYTGKDD" (not android version or anything else) ; here you will see that Google or Samsung have a lot of humour as you have to click until multiple times until having a toast displaying "You are at few clicks from being a developer" ; after something like 10 clicks, you have a toast "You are a developer"
Go "Development options" (in the "More" tab (rigjt tab of settings menu)) ; be sure that "USB debugging" is checked.
And it works ! Eclipse can see your S4(or any other device) 4.2.2 !

I had this problem today and fixed it by rebooting the Tab2 while leaving it plugged into the laptop/eclipse

Check if you have installed android-adb-tools in Ubuntu. If you do, the adb tool may be old. Uninstall and make an alias to the latest adb tool you download with the ADB plugin. To check the adb version do "adb version" if it's 1.0.29 is the old, the latest and working for Android 4.2.2 is 1.0.31.
I made a lot of stuff until i realized this.

going to Developer Options and checking USB Debugging solved it for me

My solution used on cm10.1 nightly build on droid bionic, was after updating the newest usb drivers, using the Mass storage option (instead of the MTP option for USB computer connection), then unchecking and rechecking in developer options, "ADB over network" option. Then it did the RSA pop up dialog.

For me the best solution was:
Update the Android SDK via the SDK-Manager. Removing the '.android' folder in my usr directory ( Windows 7 ) and re-plugging the device back in. Worked flawlessly due to the ADB RSA key issue. I had an older version of ADB that I stashed into c:\windows\system32\ due to not wanting to install an entire freakin SDK when all I wanted was a command prompt. Good ol' Google, the new Microsoft.

You may use an old version of adb.exe. Update platform-tools.
You may have to set a new path to adb.exe as well.

In case it helps someone else arriving here, I had this problem with a ZTE phone.
I tried installing the driver based on the offical list here but in Device Manager the driver was marked as not installed correctly.
In the end I found the way to make this work was:
Press Menu Button
Choose "Connect to PC"
Choose "Default connect type"
Choose "Install Driver"
Plug in phone and on PC select option to install the driver
Then change "Default connect type" to "PC software"
After doing this I was able to do:
adb kill-server
adb start-server
adb devices
and view my device.

It's working on windows 8 using Android 4.4.2
Reset your phone,
go to setting->about phone-> seven time click on build number.
go to back and go to developer options check USB debugging.
go to windows 8 start menu click on profile picture and click change profile picture.
Select devices and on Download over metered connections.
Connect your phone via cable your PC and wait.

ADB not recognising Nexus 4 under Windows 7

I'm running on Windows 7, and I've updated all the drivers as it says on the Android developer website regarding using hardware devices. However, Eclipse is still not recognising my Nexus 4 when I try to run the application. The Android device chooser pops up, but it doesn't show anything on the hardware section. I've turned debugging, third-party apps, and mock locations all on on my phone as well.
Is this because the phone is still new? Is there a way of making my Nexus work with Eclipse?
Nothing is showing up under ADB devices in the command prompt.

I had a similar sounding situation with my Nexus 4. For me it was an issue with the drivers Windows was installing automatically. I followed the instructions in [Q]Computer won't recognize phone? - Post #8. I had some slight differences on Windows 7.
For me I,
Uninstalled the driver from Device Manager
Let it automatically install the generic 'MTP device driver'
Right clicked on the new device and selected 'Update Driver'
Selected 'Have Disk' and pointed it to [android-sdk-dir]\extras\google
Watched an 'ADB' driver install.
Opened Eclipse to successfully run on my Nexus 4.

Just to confirm a previous comment. I needed to switch my connection to Camera (PTP) mode in addition to enabling Developer options and then selecting USB Debugging from the newly appeared Developer Options.

To enable USB debugging, go to settings, about phone and then at the bottom tap build number seven times. This will enable the developer settings where you can enable USB debugging.

To fix/install Android USB driver on Windows 7/8 32bit/64bit:
Connect your Android-powered device to your computer's USB port.
Right-click on Computer from your desktop or Windows Explorer, and
select Manage.
Select Devices in the left pane.
Locate and expand Other device in the right pane.
Right-click the device name (Nexus 7 / Nexus 5 / Nexus 4) and select Update
Driver Software. This will launch the Hardware Update Wizard.
Select Browse my computer for driver software and click Next.
Click Browse and locate the USB driver folder. (The Google USB
Driver is located in <sdk>\extras\google\usb_driver\.)
Click Next to install the driver.
If it still doesn't work try changing from MTP to PTP.

I had the same problem, but I didn't want to change to PTP mode. This is how I fixed it with MTP still enabled.
Uninstalled Google USB Driver from Eclipse in the Android SDK Manager.
Uninstalled the driver from Device Manager - click box for "delete driver from my computer"
Unplugged and re-plugged my phone into the computer.
Windows "improperly" installed drivers for the Nexus 4.
The Nexus 4 was now showing up in My Computer like a drive.
Reinstall Google USB Driver in SDK Manager.
Update Nexus 4 driver in Device Manager.
Everything works.

I had the same problem and none of the above worked, but the following solution worked for me:
On my Nexus 4:
Go to Settings
Choose Developer options (from the end of the list after pressing seven times on "About phone")
Check the "USB debugging" and press OK.

For what it's worth, in my case I was able to fix the problem simply by changing my USB connection mode from Media device (MTP) to Camera (PTP).

I had to resort to a clean install of Windows 7 x64 to fix this issue.
I tried all steps/variants in the other answers. No luck. Device Manager would show my 'Android Device / Android Composite ADB Interface' working properly with the 7.0.0.1 driver from Google, but nothing could get 'adb devices' to show my Nexus 4.
I used USBDeview to uninstall every USB device that had connected to my computer except my keyboard and mouse. No luck.
I enabled 'Show hidden devices' in Device Manager and uninstalled anything related to USB. No luck.
I added Google's vendor ID to adb_usb.ini. No luck. I deleted adb_usb.ini and ran 'android update adb'. No luck.
I brought my Nexus 4 to my brother's apartment to confirm it wasn't faulty. Worked on his machine without a hiccup.
I'm glad the clean install worked, because further troubleshooting was going to require swapping motherboards or buying a MacBook.
Boy, that escalated quickly.

Changing USB mode from MTP to PTP worked for me.

How to do it on Windows 8 (I think, it will work for Windows 7 too)
Open Android SDK Manager and delete Google Usb Driver
Open Control Panel -> Devices Manager -> Find your Nexus -> right click -> delete device
Unplug your device
Open Android SDK Manager and install Google Usb Driver
Connect your device
Open Control Panel -> Devices Manager -> Find your Nexus -> right click -> update drivers -> Manual update -> open android-sdk folder (enable checkbox for subfolders) -> install driver from Google Inc
adb kill-server; adb start-server; adb devices should show your nexus
Do not forget, that Android 4.2 now want you to submit RSA key from your computer, look at your device screen.
To enable developers options on Android 4.2: Open Settings -> About phone -> Tap on Build Number 7 times.

Just to add to the above posts for anybody struggling to get their Nexus 4 recognized by Eclipse - ADT. In the past the device was recognized by Eclipse ADT without any issues!
I ran into the same problems as the original question. Every approach I tried wouldn't work...
Toggling "USB debug" selection
Toggling "Allow 3rd party" apps selection
Allowing Mock locations
Reinstalling driver
Restarting adb.exe
Simple solution in the end
Go to Settings -> Storage -> USB Computer Condition (Menu option from Storage Screen)
Change from Media Device (MTP) to Camera (PTP)

You need to install USB drivers only if you use Windows (If you're using MAC/Linux, most likely it will work fine without any driver installations)
in the following link they describe how to do it:
http://developer.android.com/tools/extras/oem-usb.html
In short:
Connect your Android-powered device to your computer's USB port.
Right-click on Computer from your desktop or Windows Explorer, and select Manage.
Select Devices in the left pane.
Locate and expand Other device in the right pane.
Right-click the device name (such as Nexus S) and select Update Driver Software. This will launch 6. the Hardware Update Wizard.
Select Browse my computer for driver software and click Next.
Click Browse and locate the USB driver folder. (The Google USB Driver is located in \extras\google\usb_driver.)
Click Next to install the driver.

My symptoms were the composite device (this contains all of the actual USB devices such as the ADB interface, camera, etc) was not being installed. This has a hardware id of:
USB\VID_18D1&PID_4EE6&REV_0228
USB\VID_18D1&PID_4EE6
The composite device's children will have &MI_## after them. If you see those, then this is not the same issue.
I resolved this by coping usb.inf to %windir%\inf from a virtual machine of Windows 7. The hardware detected and installed fine after.

I have 2 Nexus 4 devices. One was connecting to ADB without any problems, the second one never showed up when I used the adb devices command. An additional symptom was, that the second phone did not show up as a portable device in Windows Explorer when the phone was set to Media mode.
At some point I found that a temporary solution for the second Nexus was to switch it to PTP mode. Then it was found by the adb devices command. The weired thing was that the first phone worked in both modes all the time!
Finally I found this solution that now allows me to connect both phones in both modes:
set USB mode of the phone to MTP (Media)
Using PC device manager uninstall the device ->Android Device ->Android ADB Interface
Make sure to check the box "Delete the driver software"!
then set the USB mode of the phone to PTP (Camera)
Using PC device manager uninstall the device ->Portable Devies ->Nexus 4
Then unplug the USB and plug it back in (ensuring that its set to MTP (Media) and I found that the device was correctly registered in Device manager as a ->Portable Devies ->Nexus 4
Solution found at: http://forum.xda-developers.com/showthread.php?p=34910298#post34910298
If you have a similar problem to connect your Nexus to ADB then I recommend to first switch it to PTP mode. If your problem vanishes with that step, I recommend to go through the additional steps listed above as MTP will probably be the mode you will want to set your phone to most of the time.

Follow Google's instructions for this, OEM USB Drivers.

In case none of the answers work perhaps the following clarifications will help. I followed the top answer and tried to load the program with ADB from the command line to reduce the possible complications and this did not work.
Once enabling PTP mode the ADB devices command would find my Nexus 4, but I could not push to it. I had to use Eclipse and in order for the dialog to display to accept the RSA key described below.
Note: When you connect a device running Android 4.2.2 or higher to your computer, the system shows a dialog asking whether to accept an RSA key.

On Windows 7, with Samsung Nexus S, it showed nothing in Device Manager, the adb devices command showed no devices, but when plugged in device said USB debugging was on and connected.
I used Andrea's Feb 2 answer to install the Google USB driver, which created the /gooogle/usb_driver directory and used RobertNovelo's Mar 7 answer to go to the link and follow the instructions. The device showed up in Device Manager under 'other'. I right clicked on it and selected update driver, and now it shows up in Device Manager under 'Android device', and now command line adb devices lists it.

I had a similar problem, and none of the previous solutions worked for me, and I've just solved it by myself (after a few hours of frustration), so I'm going to share my solution.
My computer suddenly stopped recognizing any Android device I've plugged in after it installed Android Composite ADB Interface for my Nexus 4. I was not able to uninstall the driver, because any attempt to do so by Device Manager was unsuccessful (Device Manager stopped responding every time).
So I've solved it this way:
Switch Windows into safe mode
Uninstall Android Composite ADB Interface
Install old SAMSUNG Android ADB Interface
Switch Windows into normal mode
Plug-in Android device (Nexus 4 in my case)
Windows recognized the device as Nexus 4
Install driver from android-sdk/extras/google folder
Everything works again! :)

I have a way to fix your problem:
Download Nexus Root Toolkit v2.0.4: http://www.wugfresh.com/nrt/
Install and select your diver and choose the Google API. For example, I chose Nexus 4 and selected Google API 4.4.4
Click "full driver installation guide..." and click step 3 tab. Choose the Google drivers.

My Windows 7 installation was not finding a driver at all. The xda-forums post has the right folder to tell Windows where the drivers are -- {SDK directory}/extras/google/usb-driver.
If you don't have the extras/Google folder + Tim Bellis, go to the SDK Manager in your IDE and look for the Google USB driver in the Extras category, and install it. I cannot tell you how to do this in Eclipse, but if you have IntelliJ IDEA, it's near the bottom of the list, checkmark it and click "Install packages".

(Windows 7) My solution to this was to find the device in Device Manager, uninstall the existing driver and install a new one from the android folder in your user account using the include subdirectories option.
All the best.

Some of you may have experienced this issue. If you don't find the USB driver (like me, I downloaded a bundle of Eclipse and the Android SDK), go to <sdk>/SDK Manager. Open it and select USB Driver from the options to install and you are ready. I had to do the PTP mode too.

If you have problems to install the ADB driver under Windows 8.1, try this solution: ADB Driver and Windows 8.1

For me, it was Nexus 4 and Windows 7. I reinstalled the drivers, changed to PTP - basically went through everything.
Clicking the tab that said MainActivity.java rather than activity_main.xml in Eclipse fixed it for me.

My solution is very silly. I had tried all the solutions above and wasted so many hours. Then I found out the solution when I browsed developer options. I didn't check mark the "USB debugging" option. The silly me assumed turns on developer options mean turns on USB debugging, but I was wrong.

It was a driver missing problem with me. I had enabled the USB debugging, tried changing the USB cable, tried reinstalling the Google USB drivers, but nothing came to my rescue.
Then ultimately I downloaded the device drivers as suggested here.
To make sure whether you have a device driver problem, go to:
Computer->right click
Manage
Device Manager
And see if you have your Nexus shown as an "Android device" or as a device in "Others".
If it shows in "Others", your problem should be resolved by downloading & extracting this and then following these steps:
Right click on your device after finding it in Device Manager as per the above mentioned three steps.
Say Update driver software.
Say Browse My computer for driver software
Pinpoint it to the location where you had downloaded the drivers from the above link.
Finally, your device will show up as follows:
As soon as you do this, a popup will show up on your device asking for permission to debug. Once you accept, you are ready!

Nexus 10 - not visible to adb on Windows 7 or Linux

adb doesn't recognize my Nexus 10 on Windows 7. Here's what I've done:
Installed the SDK and USB driver from Google. Windows 7 sees the tablet as an 'Android ADB Interface.'
Put the tablet in developer mode by clicking on 'About tablet' and clicking the build number seven times
Put the tablet in Camera (PTP) mode by going to Storage > USB Computer Connection.
Started and restarted the tablet, my computer, and the adb server repeatedly.
None of this helps. When I run 'adb devices,' it gives me an empty list. What else can I do?
Thanks.

I had the same problem on Windows 7.
First make sure the Nexus 10 developer mode and USB debugging is on ( if you dont see developer options, tap on About Settings -> Tablet -> Build Number a several time and it should activate developer mode)
Check if your ADB driver is in good shape by going into the Device Manager. If not un-install the ADB device manager and re-install it by pointing Windows to Android SDK location (It should pick up the driver automatically).
Once it is installed and still it does not work. Go into Settings-> Storage -> USB Computer Connection and select PTP option. Reconnect tablet to the USB.
Hope it helps!.

I had some problems with this as well. I was on win 8.
Install the SDK and USB driver from Google. USB driver is available in 'Android SDK Manager' in eclipse.
Put the tablet in developer mode by clicking on 'About tablet' and clicking the build number seven times (crazy)
Open Windows Device Manager and right click 'Android ADB Interface'
Click Properties
Driver Tab
Update Driver
Select 'Browse my computer for driver software' Select the 'sdk' folder under the location you installed your sdk in step 1 (e.g. D:\Dev\Software\adt-bundle-windows-x86_64-20130219\sdk)
Not sure why windows didn't auto-detect it but it didn't. Could have been because google doesn't actually 'install' the driver into windows or perhaps it was because I had the HTC USB drivers installed because of my old phone.

I started with the same problem as you, but managed to get my adb connection working on a Fedora 16 system as follows:
Inserted 0x18d1 into adb_usb.ini (I do not bother with the device ID)
Inserted the following extra line into 99-android.rules. It's not the quite the same as yours but I leave you to experiment.
SUBSYSTEM=="usb", ATTR{idVendor}=="18d1", MODE="0666", GROUP="plugdev", OWNER="johnp"
Pressed the settings->about->version number 7 times.
Rebooted tablet and noticed that a new section is created in settings called "developer options".
Enabled USB debugging in settings->about->developer options.
On Fedora performed adb kill-server.
On Fedora performed adb start-server.
On Fedora performed adb devices.
I now see a new USB device in the list. When I go to my development environment (Eclipse) I see the device there as well.

For those who are still stuck after following the other good answers, try a different USB port ...plus adb restarts just to make sure. That had me stalled for ages.

I had the same issue, but I downloaded the drivers from this application and it started working. I used this same technique on Windows 7 and Windows 8

Followed these instruction installed the correct ADB-drivers for me on Windows 7 http://developer.android.com/tools/extras/oem-usb.html

I have been struggling with the same problem for a month. I tried other Nexus 10's, other ports, other computers ... everything. I thought I tried other USB cables too, but maybe not enough, as when a friend gave me yet another cable debugging worked.
It turns out the problem for me was that the EMI protection of the PC fires off when Nexus 10 is connected via a bad cable to a bad (front-case) port. It is a big tablet, so my guess is it draws a lot of current, and this combined with a badly shielded cable makes the PC freak out.
So my suggestion to people who couldn't solve the problem in any other way is: get a good USB cable (one where the connectors are bulky - means better shielding), rather than a cheap one.
On the picture: the red cable is bad, the black one is good.
Have fun,
-Stan

All I had to do was restart the tablet.

You should have done at least two things to get your device recognized on Linux:
specify USB manufacturer and device ID in your hot-plug manager
add an entry to ~/.android/adb_usb.ini using USB manuacturer ID
You may find manufacturer and device IDs with 'lsusb' command (that's LSUSB in lower case).

As strange as it sounds, try switching the tablet between media device and camera mode. On the 10 ADB only works for me in camera mode, while on the 7 it only works in media device mode.

Try a different usb port. Worked for me on windows 8.1 with Nexus5/10.

Device not detected in Eclipse when connected with USB cable

I want to run my Android project on a device.
My device is not detected in Eclipse when I connect it with a USB cable.
I restarted Eclipse and I have checked that USB debugging is on, on the device.
Can anybody tell me what the problem is and how to resolve it?

Before starting, Make sure that USB DEBUGGING IS ENABLED in your phone settings !!!
1) BASIC STEP - Plug in device via USB, then go to device page in Android developers blog. There you can find necessary information regarding adding USB vendor ids. Add your device specific ids, and restart eclipse if needed.
2)If you were able to see the device connected(using command: 'adb devices'
) earlier, but not anymore, then just try restarting ADB. (you can use the commands: 'adb kill-server' followed by 'adb start-server'. adb commands need to be executed from platform tools folder in the Android SDK, if you havent exported it).
3)If neither of them works out and you are on windows machine,
then check the installed usb drivers are correct. If not install proper drivers
Please find more information on how to install/update drivers in http://developer.android.com/tools/extras/oem-usb.html
If this also is not working, try installing Universal ADB windows driver https://plus.google.com/103583939320326217147/posts/BQ5iYJEaaEH
4)You may also try increasing the timeout time
Go to preferences-> android->DDMS in eclipse, then try increasing 'ADB connection timeout(ms)' value
Update based on newer answers:
5)Run > Run Configurations > Target. Please make sure, the option "Always prompt to pick device" is enabled.
Special case: Windows 8 and Nexus 10 (from this question: ADB No Devices Found)
Windows 8 wouldn't recognize my Nexus 10 device. Fixed by Setting the
transfer mode to Camera (PTP) through the settings dialogue on the
device.
Settings > Storage > Menu > USB Computer connection to "Camera (PTP)"

I solve this problem by updating PC portable device drivers:
Go to : Settings -> Applications -> Development to enable USB debugging
Plug in device USB
Desktop "My Computer" right click -> "Manager"
Choose "Device Manager"
Portable Device
right click on your device -> "Update Driver software" -> Search automatically (wait about 3-5min, )
Done

Restarting the adb server, Eclipse, and device did the trick for me.
C:\Android\android-sdk\platform-tools>adb kill-server
C:\Android\android-sdk\platform-tools>adb start-server
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
I had the same problem as mentioned on this question.

I had similar problem, drivers was okey, but Eclipse did show me the device in Run > Run Configurations > Target tab. But I checked the option "Always prompt to pick device". And then running the application from Eclipse the prompt window finally showed my device.

After a long and frustrating search, finally I made my Micromax Funbook p362 to connect with eclipse and made it to suit for development.
*Installed Moborobo (All in one Android smart phone management tool).
*Perform stop -server / start -server using ADB.
*Reboot the device.
*Restart the eclipse.
*Device got detected.(Eclipse - list of adb devices)

In addition to the steps provided by #asfsafgsf (above), make sure to re-enable your phone's developer modes/functions. For my Motorola Atrix:
settings>applications>Unknown Sources: allow 3rd party apps
settings>applications>Development: to enable USB debugging, mock locations, and disable phone sleep
A note on developer modes
USB Debugging is the main mode you will need for running apps through eclipse when your phone is connected via usb (obviously). Disable phone sleep is also handy for self-explanatory reasons.
Allowing 3rd party app sources allows you to beta test your app on a larger-scale. With this, you can host your own apk and instruct your beta-testers to download it (prior to releasing it to the Google Play storefront). More specifically, 3rd party support allows the installation of android package files that don't contain a google approved signature (required for play store hosting). With 3rd party apps enabled, a handset will be able to run packages regardless of their source. You should also be able to receive an APK via bluetooth and install it in this mode.

You can also list all currently connected devices by running the following command:
adb devices

Go to http://developer.android.com/tools/extras/oem-usb.html#InstallingDriver and follow the steps on the android website but on browsing for the USB folder don't use the directory specified -> ((sdk)\extras\google\usb_driver). (sdk) just means your sdk location.
Your phone should have the correct driver and it can be accessed when you plug it in and go to the CD Driver in My Computer, in my case it's G:\drivers\adb_driver. Use this directory instead and it should work. (It may be differ with devices).

One possible reason is to check Android SDK Manager and install Google USB Driver in Extras folder if you have not installed it.
Following the steps here: http://developer.android.com/sdk/oem-usb.html#InstallingDriver allowed Eclipse to display the device.

Do following steps to detect your device in eclipse : -
On Mobile Side:- For Connect USB sync, your Android device needs to have USB Debugging enabled.
To enable Android USB Debugging Mode do following steps :-
Android 2.x - 3.x devices:
Go to Settings > Application > Development > USB Debugging.
Android 4.x devices:
Go to Settings > Developer Options > USB Debugging.
For devices running Android 4.2.2 or later, you may need to unlock Developer Options before it is available within the Menu:
Go to Android home screen.
Pull down the notification bar.
Tap "Settings"
Tap "About Device"
Tap on the "Build Number" button about 7 times.
Developer Mode should now be unlocked and available in Settings >
More > Developer Options or in Settings > Developer Options
On PC side
Connect your device to the PC with USB cable.
Download Google USB Driver
Extract/Unzip “latest_usb_driver_windows.zip” file on your computer
(using 7-zip free software, preferably)
Open device manager on your PC
Windows 7 & 8 users → search for
Device Manager from Start (or Start screen) and click to open.
Windows XP users → Google it
You will see list of all devices attached to your computer in the
device manager. Just find your device (it’ll most probably
be in the Other devices list with a yellow exclamation mark by the
name of ADB devices), then Right-click on it and select Update
Driver Software.
Select “Browse my computer for driver software” in the next window
Now click the “Browse…” button and select the “usb_driver” folder
that we extracted in Step 3 from “latest_usb_driver_windows.zip”
file.
Do NOT select the zip file, select the folder where the
contents of the zip file are extracted. And keep the Include
subfolders box checked
During the installation (as a security check) Windows may ask your
permission to install the drivers, click “Install”
Once the installation is complete you’ll see a refreshed list of
devices on the Device manager screen showing your phone’s driver
installed successfully.
Now in eclipse do following steps to install your app in your device:-
Go to Run > Run Configurations > Target tab.
Check option "Always prompt to pick device". And then running the
application from Eclipse,the prompt window finally showed
your device.

Please check whether your device is shown in the Eclipse device tab in Window > Open Perspective. If its not shown there then you need to install drivers for the the device. Once the device is visible in the Devices tab then change the launch settings for manual target. Once you launch your app then it will allow you to choose from the real device or the virtual devices

If you have the following problem
Then you can so following to fix it
Note : You should enable USB debugging on your android device(It will be in developer option in System settings)

I had this problem. With my galaxy S2. So came here for advice, but couldn't find anything specific. Then I found this 'Kies' software on the Samsung site, under the section for my exact model of phone, under downloads, after clicking software.
It installed the right USB drivers as part of the process of installing Kies and so my phone instantly then became visible on eclipse.
The Kies version for Galaxy S2 (GT I1900) = http://www.samsung.com/uk/support/model/GT-I9100LKAXEU-downloads#
There are other versions of Kies for other android models of course.

(new) device not showing, Check List:
Developer Option ON
USB debugging ON
Try changing to USB Storage/MTP/PTP
if it installs Window driver and fails, there's your problem (verify in Windows Device Manager) fix it.

ok this is an old thread -
but I spent nearly two days and did not get anywhere
Here is what solved my problem
I had USB debugging enabled ( finding developer options itself was a pain - I think the 7 times tap from google is childish and just plain stupid - rant over )
However HTC syn manager , eclipse ADT and windows computer management were all unable to identify my device
My problem was my phone was set to ONLY USB Charge - this was the problem
In 'USB Computer connection' >> Choose the option USB Storage
Once you do this - PC will install drivers and your device will get detected by Eclipse as well as in 'Computer Management' under ''Android USB devices '
Now I still dont know a way to access ''USB Computer connection' but at that time I did get the option to change and t worked
For those ( like me earlier ) who dont know how to identify if 'Computer Management' shows their device look for 'Android USB devices '
If its present - then your device is being detected by your PC
Hope this helps some others
shankar

On a kitkat Google Nexus 7, I tired everything here, and did not succeed. The device did previously connect properly to this computer.
Then I hit settings - developer-options - Revoke USB debugging authorisations
and confirmed that I really did want to revoke them.
I unplugged and plugged the USB. The tablet beeped and asked if wanted to authorise the computer for debugging. I said "Yes" and everything worked again.

For me the problem is with Defective USB Cable. I have tried those above all answers. Nothing gives me any fix. But finally i came to know the problem is because of my usb cable while changing the usb cable. While connecting through the usb cable the phone is charging but the drivers are not installed. Some usb cable don't have the option for that. So while buying check it and buy.

Best approach is install PDA net(software) on both system as well as in android device. This software automatically installs global driver for all phones, provides easy connectivity to android device.
Follow these links to download
For system
http://pdanet.co/
For android device
https://play.google.com/store/apps/details?id=com.pdanet&hl=en

Here is my checklist in windows (not the device itself) when my device is not shown:
Make sure "USB debugging is turned in setting>Developer options.
Check status bar on your device. It tells you if your phone is connected as Media Device (MTP) or Send images (PTP). My device is only listed when PTP is selected.
Turn of windows firewall.
Turn of any proxy programs ran on whole windows ports.
And finally stop adb.exe from windows task manager and wait some seconds to restart automatically.