Photos 4302 error

OK - you are navigating your backup drive using finder. This is not the way to do it.

You need to navigate to the pictures folder ON YOUR SYSTEM DRIVE (the folder with your current photos library in it)

Then you need to open up the time machine app - or "enter" time machine by right clicking the time machine icon in the top right section of the menu bar.

Make sure the pictures folder (on your system drive) is still showing in time machine. If not, navigate to it so that it is. It should show the current version of your library in there.

Then select date you want to restore from

Then right click the library and select "restore to..." so that you can choose a different folder to restore it into thereby not overwriting your current library.

See:

Restore a library from Time Machine in Photos on Mac – Apple Support (UK)

Hi

I guess you are trying to test your backup to make sure you can restore photos if needed. Is that correct?

Where is your photos library stored? The normal location is in the pictures folder. You can check, by opening preferences in the photos app.

However, if it is on an external drive, you will need to make sure time machine is backing up that drive in time machine options (Remove it from the exclude list)

If it is in pictures, open that folder in finder, then enter time machine from the icon in the menu bar, it should open time machine in the pictures folder. If it does not, first navigate to the pictures folder in time machine, then you should be able to go back in time to the older versions of the pictures folder.

PS - what do you mean by the user screen of the backup drive? And what about applications, you should not be opening applications from the backup drive, that normally won't work either.

If you mean a time machine backup, then that is expected behaviour.

A photos libray is not a single file, it is a complex structure of images, links and a database. Since time machine is an incremental backup system all the different elements (backed up at different times) are not stored in the backup in a structure that makes sense to the photos app.

You must restore the complete library to your system drive, or to an external USB drive (formatted APFS or MacOS extended) before you can open it.

Songs are single files that can be used on their own.

I photos library is a complex structure of files links and database. Time machine backs up parts of the library at different times as the individual parts are changed. (Otherwise it would have to take a copy of the whole library every time it did a backup). These are necessarily stored in different places in the backup, not in a complete library structure - so it can't be used as a library in the form it is stored on the time machine drive.