User level: Level 1 (4 points)Time Machine is not deleting old files when I try to back up with a LaCie SSD disk: I get this message: "Time Machine could not back up because the disk is full". How do I prompt Time Machine to delete the oldest back-ups to make room?
Posted on Oct 7, 2026 4:57 AM
User level: Level 10 (99,154 points)Oct 7, 2026 9:08 PM in response to JohnDory
Apple recommends using a backup drive that is twice the size of your internal drive for a reason.
Back up your Mac with Time Machine - Apple Support
Going forward, your options include erasing that backup drive and starting new backups or replace it with a 4T external drive.
Another option is to forgo using Time Machine and use CarbonCopyCloner or SuperDuper for backup.
User level: Level 10 (99,154 points)Oct 7, 2026 8:44 AM in response to JohnDory
What size and how full is your Mac's internal drive..?
What size and how full is your Time Machine external drive..?
see > Free up storage space on Mac - Apple Support
If both drives have plenty of available free space to work with.
Then It sounds like maybe Time Machine is trying to do a full backup.
User level: Level 10 (162,806 points)Oct 8, 2026 5:13 PM in response to JohnDory
"Time Machine could not back up because the disk is full".
Is the name of the disk included in that message? A screenshot would be most helpful.
Review for context: Why is Time Machine failing to do a backup because the drive is out of disk space? - Apple Community
Which drive is "the drive" is the question.
User level: Level 1 (4 points)Oct 7, 2026 6:41 PM in response to den.thed
Hi, my MacBook Pro has a 2TB hard drive, of which 880GB is free. The Lacie SSD is 2TB. It has worked fine for around 12 months and presently has 96GB free, but for some reason is not deleting the oldest files to continue backing up. The Time Machine troubleshooting page doesn't assist with this issue.
Originally posted at discussions.apple.com/thread/256371839