Photos froze when switching system photo library; after force-quit, it won't open at all

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Level 1

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Photos froze when switching system photo library; after force-quit, it won't open at all

I have encountered problems when trying to designate a copy of the original Photos library as the new system photo library.

Here is what I have done and what has happened.

I copied the library onto an external SSD.
I opened the copy. Photos opened normally, and everything from the library seemed to be present.
I went to preferences and designated the current library (i.e., the copy) as the system photo library. I got a message saying something like "iCloud photos services will be disabled. Re-enable them in Photo preferences after new system photo library is designated." I clicked OK.
Photos froze. I got the spinning pinwheel of doom. After several minutes, I force-quit Photos.
I repeated the process, opening the copy library, designating it as the system photo library, clicking OK on the "iCloud photos disabled" message, and getting the SPOD. Again, I force-quit.
I restarted the Mac.
I tried the process again. SPOD again.
I option-command-clicked the copy library. Photos opened, I clicked OK to repair the (copy) library. At some point, I got an error message.
Since then, Photos will not open either library, the original or the copy.
When I try to open Photos, either directly or by double-clicking either library in the Finder, I get a "the library could not be opened" message (see screenshot).
When I try "open other," I get a list of libraries consisting of the original and the copy. But, when I select either of them, I get a message: "The operation couldn't be completed. User is changing the system photo library" (see screenshot).

What can I do to solve this? The problem that needs solving is to get Photos to open either version of the library. Secondary goals are below, but the big one is (a) making Photos function while (b) not losing the library.

(Info about the (original) library is in a screenshot.)

The original point of this was that the Mac internal SSD is full, so I want to move the library to an external drive to clear space. Any tips on what I need to do to accomplish that without triggering this disaster again would be appreciated as well. But the primary problem is as above.

Posted on Dec 2, 2025 7:03 PM

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Answer 1

Top-ranking reply

Matti Haveri

Level 6

19,670 points

Dec 3, 2025 1:40 AM in response to J. J.

I copied the library onto an external SSD.

What format is the external drive??

Only APFS and MacOS Extended formats are supported. Non-Mac formats like exFAT are not supported and might corrupt the library. If that is the case, restore from a backup, or if that is missing, copy the library to a supported disk and hope for the best.

Or does the original open from the internal disk (via double-click or via Option-launch Photos.app and select the library)? Disconnect any external disks when trying. A detour to safe-mode might also help.

And avoid using any 3rd party virus apps or "cleaners" (CleanMyMac, MacKeeper etc) because they often produce unexpected errors and system corruption.

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Answer 2

Dec 3, 2025 7:32 AM in response to J. J.

As Matti says, the first concern is that the external drive must be formatted in either APFS format or Mac OS Extended (Journaled) format. The drive must be connected directly to the Mac by cable, not networked, clouded, NASed, etc. Additionally, the drive can not have had Time Machine on it since it was formatted. There have been so many problems with using incompatible drives that the newest macOSs won't even allow a Library on a non-Mac formatted drive to open, since there is a chance of damaging the Photos database. See this:

Move your Photos library to save space on your Mac - Apple Support

You also said that your "internal SSD is full," and that can cause all kinds of trouble, since Photos and the Mac OS require free space to be available to manipulate files. Apple recommends keeping at least 10% of your drive free, but I have had trouble even with 150GB free on a 1TB internal drive.

You didnt' say if you are using iCloud Photos or if you are using Optimize Storage. Those can be important.

If the drive is actually OK (double check with Disk Utility,) then you should try these things:

As Matti said, Re-start in Safe Mode. This bypasses certain potentially disruptive processes, and it often helps. Safe Mode is different for different computers, so see this:

Start up your Mac in safe mode - Apple Support

Use another library if you have one, or make a small test Library with a few pictures in it and see if the same thing happens. You can create a new Library by closing Photos and then option-clicking on the Photos icon.
Make a new user and see if the same problem recurs with it. This is a bit harder, because a new user can't access a different user's stuff. You would need to temporarily move your Library out of your own user's Pictuers folder up to the general "Users" folder.

You could re-build the Library, but I'd make sure everything else is OK first. If you use iCloud Photos, it’s possible that this will cause a re-sync that lasts long enough to make you nervous.

Let us know what happens…

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Answer 3

J. J. Author

Level 1

5 points

Dec 4, 2025 3:30 PM in response to Richard.Taylor

Thanks to both of you for the suggestions. It was an APFS-formatted drive.

But the problem somehow seems to have resolved itself. Perhaps it was because the internal drive was full. I've managed to clear out about 50GB on a 512GB drive (it's my parents' computer; I think they may be due an upgrade).

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