HD has 60% free space. Backup has 3% free space
The internal HD on my iMac is 1 TB. time machine is supporting my backup on a 1 TB western digital. Why does my backup only have 3% free space left when my internal HD has 60% left? wouldn't it be the same? Does this have to do with time machine? i'm pretty limited on my understanding of how stuff works.
Mountain Lion 10.8.5
iMac early 2009
Backup: Western Digital
My Passport Ultra 1 TB
iMac, OS X Mountain Lion (10.8.5)