'Photos' error code

If your "memory pen" is a flash drive it is not safe enough to keep a Photos Library there. Apple does not recommend it: Move your Photos library to save space on your Mac - Apple Support

To prevent data loss, Apple doesn't recommend storing photo libraries on external storage devices like SD cards and USB flash drives, or drives that are shared on a network.

You wrote "I backed up the photos to iCloud". To you mean, the library has been syncing with iCloud Photos Library and the sync is complete?

Then you can create a new library on a different volume and let this new library sync with iCloud Photos and download a fresh copy of your Photos Library.

Hey alibabe12,

I see that you're having some trouble opening Photos on your MacBook Pro because of an error message.

Start the Mac in safe mode for testing purposes. Safe mode can help tell us if the issue is possible login items. Be aware that internet access is limited in safe mode, but sometimes just starting in this mode and then restarting normally can resolve some issues: How to use safe mode on your Mac.

If it's still not resolved, try creating a test user account to see if the same thing happens. Creating a test user account can help determine if the issue is caused by third-party software: How to test an issue in another user account on your Mac. There's steps to take further in that resource, depending if the issue happens in the test user account or not but you can also let us know the results.

Cheers. 

The error -36 is very typical for the situation, that the Photos Library is on a volume with an incompatible file system format.

The file system format of the volume with the library should be MacOS Extended (Journaled) or APFS. If the format is different, you may be getting the file error. Try to move the Photos Library to a different volume, that has been prepared as described here:

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

If you are still getting the error, wehen you try to copy the library, move the library in smaller parts, so you can identify the items that are causing the error and can skip them. Moving a librarary in smaller parts is described here: How to avoid the Error -36 when copying a Photos Library - Apple Community

You can still 1 - open or copy files on the disk but 2 - you can't save changes to files on the disk

1 - I read that as you can copy files from the disk or read them.

2 - you can add or write files to the disk. Can you? See if you can add an image file to the memory pen. Some flash drives have a slide lock on them preventing writing to the library. Check to see if it has one and, if so, if it's in the locked position.

Léoni - I followed your instructions for copying my Photos Library to an external drive in smaller chunks. It was tedious and time consuming, but I found 4 unique files that presented the errors. Now my Photos app is referencing the new location and I have been able to free up some very valuable disk space on my internal drive. Thank you so much for always providing great answers to my issues!

Regards,

~Chris

Great, that it worked for you.

You're welcome, Chris 😊