How to solve ADB device unauthorized in Android ADB host device?

Question

When I\'m using a rooted Android device as ADB host to send adb command \"adb devices\" to Samsung S4, I received device unauthorized error message. However when I tried adb

Answer 1

Have you tried

adb kill-server
adb shell

Sometimes adb gets stuck and first killing adb server and then starting some command forces authorization window to pop-up.

Also please check adb client version on your phone. THis feature is supported from adb 1.0.31 as far as I remember.

Answer 2

Check and uncheck the USB Debugging option in the device. If that doesn't work unplug and plug in the USB a couple of times.

At some point, the device should show a message box to ask you to authorize the computer. Click yes and then the device will be authorized.

Answer 3

Experience With: ASUS ZENFONE

If at all you have faced Missing Driver for Asus Zenfones Follow This Link (http://donandroid.com/how-to-install-adb-interface-drivers-windows-7-xp-vista-623)

I tried with

1) Killing and starting adb server at adb cmd.

2) Switching Usb Debugging on and Off and ...

This is What WORKED with me.

Step 1:Remove Connection with Device and Close Eclipse

Step 2:Navigate to C:/Users/User_name/.android/

Step 3:You Will Find adb_key

Step 4:Just delete it.

Step 5.Connect again and System will ask you Again.

Step 6.Ask Device to remember RSA Key when it Prompts. I think its done.

If you Face The Same Problem after couple of days, just disable and enable USB debugging

Answer 4

• Get the public key from the client phone (adb host)

  cat /data/.android/adbkey.pub

• copy the above public key to the target phone's /data/misc/adb/adb_keys location. (you may need to stop the adb daemon first with stop adbd)

  cat /data/misc/adb/adb_keys

verify both cat outputs match.

try restarting adb daemon on target start adbd or just reboot them.

If you are having problems reading or writing to ADB KEYS in above steps, try setting environment variable ADB_KEYS_PATH with a temporary path (eg: /data/local/tmp). Refer to that link it goes into more details

    "On the host, the user public/private key pair is automatically generated,
    if it does not exist, when the adb daemon starts and is stored in
    $HOME/.android/adb_key(.pub) or in $ANDROID_SDK_HOME on windows. If needed,
    the ADB_KEYS_PATH env variable may be set to a :-separated (; under
    Windows) list of private keys, e.g. company-wide or vendor keys.

    On the device, vendors public keys are installed at build time in
    /adb_keys. User-installed keys are stored in /data/misc/adb/adb_keys"

Answer 5

Delete the folder .android from C:/users/<user name>/.android. It solved the issue for me.

Answer 6

Try this steps:

1. unplug device
2. adb kill-server
3. adb start-server
4. plug device

You need to allow Allow USB debugging in your device when popup.