Why does adb return offline after the device strin

Question

I use "adb devices" to get following result. Only one device is connected to PC by USB, but we get 8 lines of result.

Could anyone suggest the reason?

WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline
WH96TNE00361    offline

Answer 1

Try the following:

1. Unplug the usb and plug it back again.

2. Go to the Settings -> Applications -> Development of your device and uncheck the USB debugging mode and then check it back again.

3. Restart the adb on your PC. adb kill-server and then adb start-server

4. Restart your device and try again.

Answer 2

On my Galaxy Nexus with Android 4.2.2, I had the same problem initially, 'adb devices' was showing the device but with offline status (USB debugging was initially active on my device).

These are the steps I took to remedy the situation :

1. Disable USB debugging (Device not connected to PC)
2. Re enable USB debugging
3. Now connect to your PC, now a pop up on the device (not on PC) will ask you for authenticating the PC, Thats it...

adb devices now lists both device id and no offline.

Answer 3

What did me in is was that multiple unrelated software packages just happened to install adb.exe -- in particular for me (on Windoze), the phone OEM driver installation package "helpfully" also installed adb.exe into C:\windows, and this directory appears in %PATH% long before the platform-tools directory of my android SDK. Unsurprisingly, the adb.exe included in the phone OEM driver package is MUCH older than the one in the updated android sdk. So adb worked just fine for me until one day something caused me to update the windows drivers for my phone. Once I did that, absolutely NOTHING would make my phone status change from "offline" -- but the problem had nothing to do with the driver. It was simply that the driver package had installed a different adb.exe - and a MUCH older one - into a directory with higher precedence. To fix my installation I simply altered the PATH environment variable to make the sdk's adb.exe have priority. A quick check suggested to me that "lots" of different packages include adb.exe, so be careful not to insert an older one into your toolchain unintentionally.

I must really be getting old: I don't ever remember such a stupid issue taking so endlessly long to uncover.

Answer 4

I've had a similar issue with one of my phones. I was unable to connect and use usb debugging on any of my computers. In the end, I had to restart the usb debugging on the phone manually [doing so using the Developer menu was not enough].

There's only one command you have to run on your phone [I did it using Terminal Emulator app]:

adb usb

And that was it.

Hope this helps someone in the future.

Answer 5

Check that the ADB version that you are running is newer than the version of the OS on the connected devices. For me, updating the ADB helped to get the device online.

Answer 6

1. make sure the device is set for usb debugging
2. Have the adb client running (e.g. via "adb usb" or adb start-server"
3. LEAVE the device connected via usb!!!
4. AND THEN reboot the device.

This always brings my Motorola MB525 "online" again, after adb complains it would be "offline". I'm using OSX btw.