Error: device offline

Question

The emulator is running. But when I write adb shell in my shell I get:

error:device offline

What is the reason for

Answer 1

If you are on Linux or Mac, and assuming the offline device is 'emulator-5554', you can run the following:

netstat -tulpn|grep 5554

Which yields the following output:

tcp        0      0 127.0.0.1:5554          0.0.0.0:*               LISTEN      4848/emulator64-x86
tcp        0      0 127.0.0.1:5555          0.0.0.0:*               LISTEN      4848/emulator64-x86

This tells me that the process id 4848 is still listening on port 5554. You can now kill that process with:

sudo kill -9 4848

and the ghost offline-device is no more!

Answer 2

If "adb devices" lists your device but as "offline" chances are your path leads to an old version of adb (eg 1.0.29) which has problems with latest Android 4 devices. Make sure "adb version" returns 1.0.31 or greater. Starting with Android 4.2.2, you must confirm on your device that it is being attached to a trusted computer. It will work with adb version 1.0.31 and above.

Answer 3

In my case

adb kill-server
adb connect [ip_address_of_device]

Answer 4

If you are connecting through USB, unplug and plug it in again.

If you are connecting over WiFi, disable and re-enable WiFi on the phone.

Answer 5

I went to my phone settings>>Developer options>>Debugging and turned on this option: "Allow ADB debugging in charge only mode" then this problem solved for me. hope to solve for you too.

Answer 6

Make sure you're superuser.. Instead of 'adb start-server' do 'sudo adb start-server', enter your password (it will not echo), press enter. Then, 'sudo adb devices' and it will show as online.