Using an M2 Mac Studio Max w/Sequoia 15.5, I recently deployed a Samsung T9 SSD as my time machine backup location. The drive is now designated as "read only" to me. The T9 replaced an earlier hard drive where this problem did not exist. Is this an OS permission lock through Time Machine and Sequoia, and is there any way to change permissions
Mac Studio, macOS 15.5
That's normal. TM wants the whole volume for itself, and does not want you mucking about in the structure manually only through the TM interface.
Not sure why you are looking to write to the drive yourself, but if you format the external SSD as APFS and set up multiple volumes, you can designate one volume as the TM backup (select it as the backup destination) and use the other volume(s) as regular storage. You should consider the wisdom of that, personally I think it's better to keep backups separate and follow the 3-2-1 backup rule. However, I did set up multiple volumes on the pair of 4 TB Samsung T7 that I use for TM backups of multiple Macs, so each Mac is limited to an appropriate amount of space for the backup.
That's normal. TM wants the whole volume for itself, and does not want you mucking about in the structure manually only through the TM interface.
Not sure why you are looking to write to the drive yourself, but if you format the external SSD as APFS and set up multiple volumes, you can designate one volume as the TM backup (select it as the backup destination) and use the other volume(s) as regular storage. You should consider the wisdom of that, personally I think it's better to keep backups separate and follow the 3-2-1 backup rule. However, I did set up multiple volumes on the pair of 4 TB Samsung T7 that I use for TM backups of multiple Macs, so each Mac is limited to an appropriate amount of space for the backup.
This is how Time Machine works. A backup drive can not be used for other purposes so there is no user write permission on the drive. See Back up your Mac with Time Machine - Apple Support
Make sure to read the footnote in the article at the above link as there are exceptions.
Haudeda wrote:
It's possible that the permissions issue is related to how the Samsung T9 SSD was formatted or set up for Time Machine. You can try to reformat the SSD specifically for Time Machine to see if that resolves the read-only issue.
Sorry but not sure where you are getting your information ?
Whether the external drive was formatted using the newer APFS / GUID Partition Map or older Mac OS Extended / GUID Partition Map
Time Machine Backup would mark the drive as Read Only which my colleague @ BobTheFisherman has outlined
It's possible that the permissions issue is related to how the Samsung T9 SSD was formatted or set up for Time Machine. You can try to reformat the SSD specifically for Time Machine to see if that resolves the read-only issue.
Dear Neuroanatomist,
Thanks for your thoughtful reply; a lot of things that I want to store are archived items that I do not regularly keep on my Mac Studio internal SSD, so it's just another way to store them somewhere else. I suppose that, after giving this some thought, I should buy another lesser capacity SSD and put my archived items on that one. I see no need of subdivisions on my backup external SSD and totally agree with your 3-2-1 backup strategy. I appreciate you weighting in on this and lending your experience. Thanks again!
Thank you Bob! This is a change from the other OS permissions and use of a hard drive that I have encountered. Your answer clears it up for me and I appreciate you taking the time to respond.
Time Machine Backups on outboard Samsung T9 SSD permissions question.
