See my response here: Temporary solution to TimeMachine Backup issues (fails after the first backup)
You must set time machine size to 100% and use a quota-limited user if you want to limit the backup size.
See my response here: Temporary solution to TimeMachine Backup issues (fails after the first backup)
You must set time machine size to 100% and use a quota-limited user if you want to limit the backup size.