Mac OS X 10.8.4 Time Machine stops backing up to external disk
Since the mandatory upgrade to Mountain Lion last summer I have not had a successful backup to my external hard drive (LaCie).
LaCie used to overwrite new backups over old backups, but hasn't since I installed Mountain Lion.
Any ideas on how to get Mac to cooperate with LaCie?
iMac, OS X Mountain Lion (10.8.4), 500GB LaCie d2 HD Quadra 7200 rpm