Editing in Photos

This issue has been taken up in different discussions on this site. I have analyzed this error, which is characterized by the following behaviors: (1) photo is shown in lower quality than the original, (2) editing is impossible and produces the well-known error "Photos cannot load adjustments for this image", (3) it is not possible to reset the adjustments, (4) editing in any other application produces an error, and (5) exporting the unmodified original is not possible as it produces an "Unknown error (4)". Repairing the library reports success but does in fact NOT solve the problem. I have also examined the place where Photos keeps originals and the files for the affected pictures are NOT THERE ANYMORE. From these behaviors it seems that Photos has lost the original and the library is left with a low-resolution preview. Not sure why and when this bug started manifesting itself, but I noticed it first in Mojave and it persists in Catalina. It seems to affect some photos from 2015. I have not found any working solution and it is unlike that a fix can ever be found, since indeed the originals of the affected pictures cannot be found in the photoslibrary. They have simply vanished. This is a serious bug for which Apple has not given any clear explanation as far as I can see.

1 - As a test launch Photos with the Option key held down and create a new, test library.  Import some photos and test to see if the same problem persists. Does it? (This tells us if the problem is limited to your current library or is more wide spread)

2 - Next log into another user account and see if the problem persists there in Photos. (This tells us if the problem is limited to your user account or is system wide).

3 - Boot into Safe Mode (Use Safe Mode to isoloate issues with your Mac) and test Photos editing there. Reboot normally and test again.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing some system cache cleaning, volume verifying and directory repairing. 

In 2015 I did migrate to a different machine which implies that all my files including my photos library were RESTORED FROM A TIME MACHINE BACKUP.

Is this particular backup still on your Time Machine volume? Or has it been overwritten by now? It would help to know, if these original images have already been missing when you restored the backup.

Can you go back in time on Time Machine and find out when the originals vanished?

There are three possible reasons for missing originals -

• They may not yet have been synced to the Mac by iCloud Photos, even if you are not using "Optimize Storage". This happens occasionally for photos with large additional content - Portrait Mode photos, where the depth map may be missing, Live Photos with a missing video component, photos taken with a second larger version. If Photos has not fully downloaded all originals, your backup may be incomplete.
• Photos may have recovered incomplete versions - orphaned items - when repairing the library.
• The library may have been damaged by running cleaning applications. Some duplicate cleaners are removing the original image files and replacing them by the edited versions.

Where is your Photos Library stored, Koenraad? Is it in your Pictures folder or on external volume?

When did this problem with the lost originals start? After a system upgrade? Or did ou restore the library from a backup?

I can consistently reproduce this behavior, but ONLY on photos that were taken using "capture outside the frame" enabled; AND if I have "optimize Mac storage" enabled in the photos app.

Any other photos work fine.

If I select "download originals to this Mac," all photos edit fine, including the "capture outside the frame" ones.

This is reproducible across several Macs, and only happens in Catalina.

cjmildenberg: interesting observation. This suggests that your error is different from the one I reported, even if we see some similar behaviors. Differences are the following: my error only affects older photos which have previously been edited (photos that were never edited are okay); my error was observed even in Mojave, so before Catalina; and there is no way I can download the originals, as they have totally disappeared from the originals folder.

Leonie: My photos library is in the standard place Pictures > Photos Library.photoslibrary. The problem was first observed in Mojave, when I attempted to edit some older pictures that had been edited before (hundreds of those pictures are affected, whereas pictures that were never edited are just fine).

In 2015 I did migrate to a different machine which implies that all my files including my photos library were RESTORED FROM A TIME MACHINE BACKUP. This may be relevant, since it seems that the affected pictures were initially edited on the previous machine.

Many of us here use the following backup strategy: 1 - Time Machine to backup boot drive and any external data hard drives; 2 - an external HD which is a clone of the boot drive. This lets us boot into it if the internal boot drive has any problems and lets us trouble shoot. I update the cloned disk once a week. Worse case scenario of the internal boot drive totally corrupted: we can boot into the external boot drive, erase the internal and clone the external to the internal. Then data filers can be brought up to date via Time Machine.