How much extra space needed for backup?

[kathykate]

I have a partitioned 1tb ext. hd of which 300Gb is given over to a daily backup of my user files. My user file totals 266GB. Yet backups are failing - I'm getting an error message saying no space left on disk. When I go the Disk Utility and check space on the partition it says that 297GB is being used, and only 2.52GB left.

Why is more space being used than is being backed up? Is 00GB not enough space for a user file which is 266GB?

I'm backing up using smart backup.

Any info gladly received!

[dnanian]

Take a look at the Troubleshooting section of the User's Guide, which tries to explain in some detail how this kind of thing can happen with Smart Update...

[kathykate]

Thanks for that, am erasing and recopying as I type.