How to fix ADB „error: insufficient permissions for device“

Problem:

Why trying to access your Android device using ADB, you encounter the following error:

error: insufficient permissions for device

Solution:

The problem seem to be related to the one I described earlier.

For some reason, the ADB permission server has not been started as root.

So, kill the ADB server by executing (as the non-root-user you normally use):

adb kill-server

After that, you should restart the ADB USB service:

sudo adb usb

If that didn’t work, try running the

adb kill-server

command as root and repeat the adb usb command.

If even that can’t get it to work, try rebooting.