"Photos cannot load adjustments for this image" error since upgrading to Catalina

I was able to determine a difference in the plist for a "bad" photo (= affected by the issue) and a "good" photo (= not affected by the issue):

Good photo:

adjustmentEditorBundleID = com.apple.Photos (upper case P)

adjustmentFormatVersion = 1.5

Bad photo:

adjustmentEditorBundleID = com.apple.photos (lower case p)

adjustmentFormatVersion = 1.4

Hypothesis: the photos that were edited in Aperture and migrated to Photos (years before the migration from Mojave to Catelina) have adjustmentFormatVersion 1.4 and I suspect that Catalina Photos cannot parse adjustmentFormatVersion 1.4 since support for Apterture was removed.

Or maybe, Photos is confused by the uppercase P versus lowecase p (see https://stackoverflow.com/questions/7688379/is-bundle-id-case-sensitive)

Maybe it is related to this: "In June 2014, Apple announced that development of Aperture has been discontinued. Since then, Apple has released six major macOS upgrades. For technical reasons, macOS Mojave is the last version of macOS to run Aperture. Starting with macOS Catalina, Aperture is no longer compatible with macOS."

https://support.apple.com/en-us/HT209594

I suspect (but am not 100% sure) that the affected photos in migrated photo library were at some point edited by Aperture.

Just to be clear: I am *not* trying to edit any photos using Aperture on Catalina. I was using Photos before the migration to Catalina and also after the migration to Catalina. I am only saying that my photos library likely contained some photos that at some point were edited with Aperture.

While debugging the issue, I discovered another and likely more important difference between "good" and "bad" post-migration photos on the new MacBook 2020 running Catalina:

• "good" photos have a JPEG file some where in the originals directory in the Photos library.

• "bad" photos do NOT have a JPEG file somewhere in the originals directory in the Photos library.

Also, I found some interesting differences in the pre-migration photos on the old MacBook 2016 running Mojave:

• "good" photos have:
  • path = empty
  • ismissing = True

• "bad" photos have:
  • path = a fully qualified path pointing somewhere into the Masters/<year>/<month>/<day>/<timestamp>/... directory in the photos library
  • ismissing = False

I reported this issue to Apple support and it was escalated to Apple engineering by the end of August. On 8-Sep-2020 I received the following update (translated from Dutch):

We have called you, but we have not been able to reach you. I wanted to call you about an update as a result of our contact because of the error message you get when exporting photos.

My colleague at head office has indicated that they have already received some other reports about this. With the data they have received from you and the other cases, they will investigate what is going on. At this point, I have no further information and can only ask you to wait. If the failure turns out to be on our side, a future software update will be able to solve the problem. Therefore, make sure to download any updates as soon as they become available, and then try exporting a photo again.

If we find something else on our end, we will contact you to ask for more information, or hopefully offer a solution.

If you yourself start to notice other symptoms (other error messages, the malfunction continues to spread, etc.), or if you have found a solution or workaround yourself, we would like to hear from you. We can then share that information with headquarters.

The same or very similar issue is reported in many other threads (none have a fix):

https://discussions.apple.com/thread/250932769

https://discussions.apple.com/thread/250852440

https://discussions.apple.com/thread/250870058

https://discussions.apple.com/thread/250771558

https://discussions.apple.com/thread/251094038

https://discussions.apple.com/thread/251245094

Three different symptoms of the affected photos:

Duplicate photo:

Error = Failed to download assets for duplication

Edit photo:

Error = Cannot Start Editing, Photos cannot load adjustments for this image.

Export photo:

Error = Unknown Error (4)

:-)

While trying various other workaround, I discovered yet another symptom of the affected photos: right-click on photo => Duplicate 1 photo => error "Failed to download assets for duplication"

My support case with Apple has been open now for 3 months (since 10 October). Since a large number of photos in my photos library cannot be exported nor edited, they are essentially LOST to me. It is infuriating that Apple is not taking this seriously. When Adobe Lightroom lost user's photos (also back in August) it was a huge deal.

More threads the report the same problem (once again, none of them have a resolution):

https://discussions.apple.com/thread/251036700

https://discussions.apple.com/thread/251382514

I just completed a photos library repair (it took several days to complete) but it does not fix the issue.

Apple tech support has escalated this issue to Apple engineering on 13-Aug-2020