After installing Sonoma, Photos was unable to open the library “Photos Library”. (5600)

DS, this happened to me too after upgrading to Ventura. Sorry to see you got no responses here, but that's the only thing that's letting me post a reply after so many months. (Most of the other threads on this topic have been closed, which is a shame because it means I can't share a possible solution with those people.)

I called Apple support. They didn't have a description of the '5600' error, but we were able to fix the problem in the end with this procedure:

1. Create a new user account. (She said to give it admin privileges, but I now realise I forgot to do this, and just left it as a standard account.)
2. With the external drive still connected, log out from your usual account and log in to the new account.
3. Open the Photos app with the Option key held down and select the Photos library from your external drive.
4. With any luck, the Photos app will now update the library. (This took about 5 minutes for me.) Once that is complete, verify that your library has opened successfully.
5. Quit out of Photos and log out of the user account.
6. Log back in to your own account and launch Photos again. (This time it said it was updating the library again, with it immediately at 93% complete. Then it briefly said 'Restoring' (from memory), then the library successfully opened.)

As a final test, I quit Photos, ejected the SSD, plugged it in again and restarted Photos. The library loaded successfully again.

Hope that helps someone!!

UPDATE: My fix was short lived. I plugged the drive in again today, and hit the same error again. Logging out and in again with the drive plugged in got it working again, so that seems to be a reliable workaround. But the permanent fix I had hoped for remains elusive.

Oh no, that sounds frustrating!

When you see the "100% updating complete" message followed by a 5600 error, it usually indicates that the Photos app is having trouble accessing or processing your photo library.

Here are some steps you can try to resolve the issue:

1. **Restart your Mac**: Sometimes, a simple restart can resolve issues like this.

2. **Update Photos app**: Ensure you're running the latest version of the Photos app. You can check for updates by going to the App Store and clicking on the "Updates" tab.

3. **Rebuild the Photos library**: This can help fix any issues with the library itself. To do this:

* Quit the Photos app.

* Press and hold the Option key while opening the Photos app.

* Select "Repair" from the menu that appears.

* Follow the prompts to rebuild your library.

4. **Check your disk space**: Make sure you have enough free space on your Mac's hard drive. You can check this by going to the Apple menu > About This Mac > Storage.

5. **Check your iCloud settings**: If you're using iCloud to sync your photos, try disabling and re-enabling iCloud Photos to see if it resolves the issue. You can do this by going to System Preferences > Apple ID > iCloud > Photos.

6. **Reset the Photos app**: If all else fails, you can try resetting the Photos app. To do this:

* Quit the Photos app.

* Go to the Applications folder and find the Photos app.

* Right-click (or Control-click) on the Photos app and select "Show Package Contents".

* Navigate to the "Contents" folder and delete the "Photos Library.photoslibrary" file.

* Relaunch the Photos app.

If none of these steps resolve the issue, you may want to reach out to Apple Support for further assistance.

I hope this helps! 🤞

I doubt that your step "6." is possible, unless you modify the system. All apps preinstalled as a part of the system on a Mac are protected by the System Integrity Protection and cannot be modified, even by the root user, to prevent malware from installing Trojans. It should not be possible to remove a part of the package of the Photos.app, as it is a part of the protected System software.

Is it a Typo and are you suggesting to modify the Photos Library?

léonie said: I doubt that your step "6." is possible,

I don't even have a "Photos Library.photoslibrary" file inside the Photos app. And if I weren't using iCloud, then removing the Library would be bad bad. I can't imagine what this means...

Adiabatic-Lapse:

Regarding Step # 6: can you post a screen shot of the Contents folder showing the Photos Library.photoslibrary file? I don't have that file anywhere in the Photos app. This is with Photos Version 8.0 (560.0.110) with Ventura.

Thanks for those suggestions.

1. Yep. Always my number 1 go-to as well. Restarting (or even just logging out and back in) is a temporary, but not permanent, fix.
2. I can try updating macOS and Photos.
3. I think I remember seeing that someone else did this and it didn’t fix the problem. Also, given that the library works just fine after logging out and in, I don’t imagine that’s the problem.
4. Disk space isn’t a problem.
5. I don’t use iCloud Photos.
6. I can see there are different opinions on that suggestion.

The remove option, like in the phone. Not a total delete.