same insue
Same insue.
mac 10.6.8
before, ios 6.1.3 iTunes 11.0.5, sync and backup fine.
after, ios 7 gm, iTunes 11.1b(48), sync works, but can not find any backup.
i have a ipod 4th, with previous backup, but can't find this one too.
rollback to itunes 11.0.5 (you need to change library file with old library file, because itunes says that can not open the newer file)
rollback to ios 6.1.3...
and the same alert, the backup can't be done...