Never ran into this one before. I have a USB stick that I regularly use for my robot backups, and has never had any issues before. But on the same robot, only an hour apart, I had a successful AoA backup to this stick, followed by a failure.
The robot is an R30iB, running version 8.20P. With the USB stick in UD1, it seemed to be running slowly (this robot is heavily loaded, the AoA backup comes out at about 5MB), then while backing up one of the .DG files, the robot threw a "unable to copy" error, and gave me Continue and Cancel options. I chose Continue, and the backup appeared to do the rest of the files without further incident, but once the backup process was done, the robot threw the 062 error. This happened 3 times in a row (same file each time) before I punted.
I tried a different USB stick, this time in UT1, and that took an AoA backup without any errors. While waiting for that, I checked my original USB stick, but it still had 1GB of free space, and no errors that Windows Scandisk could pick up.
Odd. Not a showstopper, but very curious.