I have a large (650GB) photos library sitting on a fast external hard drive that's attached to a Mac Mini (with M2). After I upgraded to Sonoma, I can't open the Photos app. It tried to repair and than restore but couldn't do it. Any suggestions?
Apple has documented the requirements for the file system format since Photos first has been released. It has been the same for the previous photo applications released by Apple (Aperture and iPhoto). Putting the library on a volume with an incompatible filesystem format can result in ambiguous filenames and pathnames, and Photos may not be able to retrieve all image files correctly or videos may not be able to play, because they cannot find the resource fork.
Apple's instructions on how to prepare an external drive for Photos are here: Move your Photos library to save space on your Mac - Apple Support
I have the same problem, without an external drive. On my Macbook Air, i asked to repair permissions, and it tries to, and then says that it can't repair the permissions. Help!
It's formatted ExFat
And that's the problem. It's not a problem now, it always has been. Having the library on an inappropriately formatted disk can lead to silent corruption of the database and dataloss. Now Photos is more rigorous in checking for this, which is good.
Yup the problem is the drive is formatted with exFAT. Sonoma has been failing to mount exFAT drives.
I had some external hard drives formatted in exFAT. Disk Utility didn't mount them...name grayed out in left column. I ended up using EaseUS software to let me into the unmounted drive so I could copy files to another drive (formatted APFS). Was software recommended on MacWorld. Cost about $100 for one month's use of software but so worth it. EaseUS did take about 10 hours to scan my 10 TB drive. I couldn't simply copy over the whole drive, or I didn't understand how to. If you copy a folder, all you get is the folder and not the contents, so I had to select individual files to copy over. Some files were corrupted, but I was able to copy all my photos and video clips.
I'm now investing in lots of cheapish external drives so I can have 3 copies on separate drives of anything that's critical to keep.
What format is the external and how are you connected to it? It needs to be formatted Mac OS X Extended, Journaled or apfs and directly connected, not on a network share.
It's formatted ExFat it's plugged in to a USB-C port. I've been using it for a long time with no problems. Why is it an issue now?
Photos lib on external HD won't open after upgrade to Sonoma
