Photos unable to open library after Catalina update (error 4302)

I was having the same problem as all of you after I upgraded. For days I've been trying to upgrade the Photos database which is located on an external drive. It would take hours and then throw the 4302 error. I tried it again and again just to bang my head against the wall. I finally looked at my drive and it was low on available disk space. 500mb. I cleared that drive's superfluous movie files and gained about 50gb. After I did that I upgraded the database with no problem.

For me the fix was create more space on the drive. It seems while Photos is updating it is also writing out some temp file(s) which pushed my storage beyond what was available. The size of my Library remained the same after the upgrade. 1.97TB.

Myself and others who experienced this issue have been successful in deleting the current library and replacing it with a backup. I was able to restore a version from Time Machine and Photos was able to open and upgrade it properly without issue. I highly suggest anyone experiencing this problem give that a try as it seems to be the most successful means for most at this point.

My library is located in a external drive and sizes nearly 40 GB

Is the file system of the external drive compatible with Photos? It should be MacOS Extended (Journaled) or APFs, the external drive must not be used for Time Machine backups, and and it should have a wired connection.

Then all is as it should be. Have you tried to check the external volume with Disk Utility? You could run the First Aid from on the drive.

And then try to set the "ignore ownership" flag on the volume as described in this document:

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

Perhaps this will make it possible to repair the Photos Library.

One possible reason for Photos not being able to open the library may be incompatibe image files or videos in the library. Photos on Catalina cannot process all media formats that have been supported on older systems.

When I could not open a library after the upgrade, the only thing that helped has been to download the library from iCloud to a new, empty library. But that will not work in your case, since you are not using iCloud Photos.

Do you have a backup copy of the Library, that you could use as a starting point to recreate the library?

Or access to a mac running Mojave, so you could try to open the library in Photos 4.0 with Mojave? If there are media files in your library, that are not compatible with Photos 5.0, you might be able to remove them in Photos 4.0 on Mojave, if Photos 4.0 still can open the library after the failed attempt to open it in Photos 5.0.

When you look at the package contents of your Photos Library in the Finder - does it still show the Masters folder with yearly subfolders, or has it already been converted to a flat "Originals" folder?

package contents of th

I was able to resolve my issue by deleting the original library and restoring it with a copy from Time Machine. It took hours to update the library but it was all loaded and seems to be functioning now this morning.

A reinstall did not help for me. But this fix posted here did solve this issue for me: https://discussions.apple.com/thread/250715231?answerId=251497034022#251497034022

Just delete the files referenced there. Then try to upgrade the library again. It worked for me.

In my case my external drive was not behaving (could not create folders, eject it, etc), force ejecting it and repairing it in Disk Utility allowed Photos to open my library

Update. Free up space on the external harddisk where the photo library is on, solved the issue for me!

I had the same issue, but it's gone now.

Just reinstall Catarina from recovery mode. After it's done, run Photos. Updating the library started. After roughly one hour for 200 GB library, photos started to fill the window. It's still rebuilding all the albums now. But I wanted to share the good news to you guys ASAP.

The "fix" is outlined above. Re-install Catalina from the recovery partition and then re-open your photo library. Worked for me.

Short reaction on earlier posts in this thread.

Just read that opening the library in the former OS in not possible.

Have more than 600 GB left on my Macintosh HD. But on my external hard disk were my photo library is on, during the conversion there is hardly any memory left (49 KB available). So, I will wait for the third conversion to be finished, and if the conversion is unsuccessful, I will see how much free space is available, make more space available (if necessary) and give it another try...

No. It's not a library from backup. I don't know the version number but the one sits in the Pictures folder and Photos claimed that The Library could not be opened after Catarina update . I have the whole library in iCloud in full resolution so that I knew I could probably rebuild a new library from that. But I also knew that it will take forever with my slow internet connection. After reinstalling Catarina, Photos magically recognized the same library and began to update it. Everything was automatic and no tweaking was needed.

To reinstall Catarina, just restart your Mac and hold Command + R. The rest is self explanatory. I hope that you can get the experience as mine.

Has anyone tried the 10.15.1 updated? it seems to have some "Photos" fixes but doesn't say anything about this particular issue.

( https://support.apple.com/en-us/HT210642)