I'm having the same problem "Please check the confirmation dialog on your device", but there is no such dialog on the device.
Things I tried and DID NOT SOLVE:
1) Remove /data/misc/adb/* - Failed, there was nothing there (full wipe before flash a new rom)
2) Try different ROMs - Failed, tried AOKP Milestone 1 and 2 and CM10. Dialog never showed up.
3) Try different usb cable OR usb port - Failed, adb is recognized, but no confirmation dialog on the device (device shows as unauthorized)
4) Removed all drivers and installed them again - Failed, same problem;
5) Updated android-sdk (or full delete and reinstall [remembering to adb kill-server]) - Failed, problem continues even with platform-tools up-to-date.
6) Removed all folder C:\Users\Myself\.android - Failed, it was never recreated;
7) Tried to connect via adb over wifi, device is found but unauthorized persists;
Things that gave me some clues:
1) Reboot to recovery mode allowed me to use ADB without any authorization (only while in recovery);
2) Recovery sideload works without any problem;
3) HOWEVER, when connecting to another computer (Windows XP, fresh install on a virtual machine), dialog appears and adb works!
1) Devices tried: Galaxy Nexus / Galaxy S3 I9300
2) ROMs tried: AOKP (4.2.2) / CM10 (4.2.2)
3) Windows 7 x64
The problem is on the computer side, that's a fact. However, I would like to SOLVE it without having to reformat my computer, or change my OS.
Where to start?