I have a Nexus 4 with Android 4.3 and I am trying to connect the device to a computer with Windows 7 64bit.
I installed the latest drivers and the latest adb
version. I think I tried almost everything and I still get the following message:
C:\Program Files (x86)\Android\sdk\platform-tools>adb devices
List of devices attached
007667324ccb229b unauthorized
What can be the reason for this error?
When I turn off my Comodo Antivirus everything goes back normal. All other solutions suggested here went in vain. Somehow I figured out one solution.
If you are using Comodo Antivirus (Version 6.3/ For other versions search for similar options) the following solution would help you.
Open Comodo > Tasks > Advanced Tasks > Open Advanced Settings > Security Settings > Firewall > Firewall Settings > Advanced : Filter loopback traffic (e.g. 127.x.x.x, ::1)
Uncheck this "Filter loopback traffic" option, which prevents adb from normal working.
Simply re-plugging did the trick for me.... The permissions-dialog didn't show up the first time I plugged in the device, the second time it did and everything is fine now.
Similar to Flavio's answer (https://stackoverflow.com/a/18542792/1064996), it was something to do with the files in
~/.android
(on the host machine, not the phone).I didn't have
~/.android/adbkey
, but I did have~/.android/debug.keystore
and my whole~/.android
directory was owned by root. I removed the keystore file and also changed ownership to me (sudo chown -R $USER ~/.android
), killed the adb server and plugged in my phone, and it worked.It was probably the ownership thing. Make sure you have read/write permissions in
~/.android
Four easy steps
./adb kill-server
./adb start-server
replug the device, unlock it and accept the new key
Use a different USB cable. Some cables may not have all pins connected or whatnot, and while they work for image transfer, the debugging/adb does not work.
The bottom line: I kid you not. A cable which works for my phone (adb works) does NOT work for my tablet - the device is always offline or unauthorized and tablet pops out no dialog. I tried multiple reboots, settings, I went berserk in the process and cursed the bloody Android. Then accidentally I plugged in the cable which came with the tablet and suddenly it worked. My fascination with Android is definitely gone. What a stupid piece of junk.
It happened for me after my backup software changed the permission to my user directory. I opened it in File Explorer, it prompted me to set permissions and it fixed the issue.
FYI: Android has a special directory under "\User\.android" If you can't access it, it won't prompt you.