time machine won't backup to attached hard drive because the startup disk is full. Startup has 3 GB of free space out of 150 GB. Backup drive has +900 GB free space. The startup is one of two APFS volumes on the 500 GB internal drive. The backup is one of six APFS Volumes on a 6 TB Seagate drive. The machine is a early 2015 Mac Air using Monterey.
MacBook Air 13″, macOS 12.6
It doesn't have enough room to make a snapshot. You must clear some files off the drive in order for it to write the snapshot.
The APFS backup format makes a snapshot on the source drive, then copies it to the backup drive.
You need to keep 20 to 30 GB free on that drive for it to function properly, much less create a backup.
To follow on the advise from previous Contributor.
It is generally a good computer practice to alway keep at least 15% to 20% of the Total Drive Capacity’s as Empty Space.
Allowing the computer to drop below these guidelines may eventually, cause unintended consequences like that which are happening now on this machine.
The links below will assist in identifying what is taking up space on the Internal Drive and provide possible ways to remove data that is under the direct control of the User ( Home Folder ) .
Additional info on the storage size
went through all storage optimization steps found on line including an attempt to decrease the System Data size, currently at 104 of 150. All efforts have been to no avail.
I'm backing up a bootable CCC copy and will reformat the disk so Monterey can utilize the full 500 GB. I suspect that the System Data will once again build up to a manageable size. Is there a method to control the size. I read Apple is suppose to restrict the size to 20GB
Thanks
I was unaware of that requirement
Bill
time machine won't backup to attached hard drive because the startup disk is full
