Catalina Photos "The export operation failed to create af file for the photo identified below" "Unknown Error (4)"

"Being able to export photos is an important function," => I agree. If I cannot export the photo (neither the original nor the edited version) Photos has essentially "lost" the photo as far as I am concerned. Very serious indeed.

"It sounds like some photos export as expected, while others consistently give you the error described." => That is correct.

"Are there any common factors between the photos that do not export, like a specific file format?" => The only pattern that I notice is that the photos that cannot be exported tend to be the older ones (= the photo was taken and first stored into the library a long time ago).

Some possible relevant pieces of additional information:

(1) I recently moved my photos library from an older laptop (early 2016 MacBook Retina running Mojave) to a new 2020 MacBook Air 13" running Catalina. I used the migration tool in combination with a time machine backup. I am only using the new MacBook to edit the library, but I did not remove photos nor the library from the old MacBook (yet).

(2) I also have other pressing issues with Photos on the new MacBook: see https://discussions.apple.com/thread/251652645 for example. That issue includes a stack trace of a hung Photos application.

"Give that a try with these steps: How to use the Photos library repair tool" => I am worried by the comment "If you repair a library that's automatically updated with iCloud Photos, the entire contents of the library re-updates with iCloud after the repair process completes." If I follow these instructions, will this cause my entire library to be re-uploaded? My entire library is more than 1 Tera-byte and my Internet is not very reliable or fast. This may never converge.

Hi Joseph_S:

Here are the results of the 1st experiment that I did (I plan to do some more).

On my new MacBook 2020, I tried to export a single old photo (from 2012).

I initiated the export after my Photos application had already been up and running for at least 10 hours (this will be relevant later below).

The export was started but made no progress, not matter how long I waited: the progress bar was stuck at 0%.

Note that is different behavior from what I saw before: previously I got an "Unknown Error (4)", this time it got stuck. (This is why I will try to do some more experiments, to see if I can reproduce the Error 4).

While the export was still stuck, I tried to Quit Photos. Photos informed me that an export was still in progress, and I selected Quit anyway from the dialog. At that point, Photos was completely stuck, and did not actually quit no matter how long I waited.

The CPU went up to 100% (process photolibraryd) and the cooling fan started blowing. I used the ActivityMonitor to take a sample of photolibraryd (attached).

Note that this is very simimlar behavior to Enhance being stuck (reported here: https://discussions.apple.com/thread/251652645).

At that point, I force quit photos and restarted my laptop.

When the laptop finished restarting, I immediately restarted Photos and tried to export the same photo again. This time it worked fine.

It appears that something gets stuck when Photos has been running for some time (this is consistent with my experience in the Group Enhance issue).

I tried exporting the same photo from my old MacBook 2016. That worked fine the first time.

Note that my old MacBook has iCloud Photos set to "Optimize Mac Storage" (it has a small harddisk) while my new MacBook has iCloud Photos set to "Download Originals to Mac" (I bought my new MacBook 2020 with 2TB disk specifically for this reason).

@ryanne77: The problem still happens when I boot in safe mode.

@ryanne77: New clue: when I try to edit one of the affected photos in the Photos app on the new MacBook, I get a "Cannot Start Editing: Photos cannot load adjustments for this image" error. Screenshot at https://imgur.com/nOi4a4K

@leonie: The files are JPEG. When I downloaded from iCloud I tried both "unmodified original" and "most compatible": both work.

Detailed current state:

* I have selected 3 Photos that consistently reproduce the issue for the experiments described below. (There are many thousands of other photos that also have the issue.)

* The Photos application on the new MacBook 2020 (Catalina) consistently reports "Unknown Error (4)" when I try to export the photos. It fails for both for normal export and "export unmodified original"

* When I try to edit one of the affected photos in the Photos app on the new MacBook, I get a "Cannot Start Editing: Photos cannot load adjustments for this image" error. Screenshot at https://imgur.com/nOi4a4K

* When I boot my new MacBook 2020 in "Safe Mode", the problem persists. Any attempt to export the photos still results in the same "Unknown Error (4)". I made sure that I actually was in safe mode: there was a red "Safe Boot" message in the top right of my screen.

* Possibly unrelated to the issue at hand: while in safe mode, I did notice that my MacBook was noticeably slower. All animations were stuttering. Repainting of the screen was slow (about 50ms per repaint) and I could clearly see the screen being repainted in horizontal bands.

* The Photos application on the old MacBook 2016 (Mojave) with the same Photos library (before it was migrated to the new MacBook and still synced to the same iCloud) consistently exports the photos successfully. It succeeds for both for normal export and "export unmodified original"

* The iCloud web-based photos application (using a browser) consistently downloads the photos successfully. It succeeds for both "download unmodified original" and "download mosts compatible including edits" in the "secret" drop-down menu.

* However, the first time (and only the first time) I tried to open the album in the iCloud web-based photos application I got an error message "Photos has stopped responding. An error has prevented this application from working properly." I selected "Send to Apple". This happened 6-Aug-2020 9:05am Netherlands time. I was using a Chrome 84.0.4147.105 browser. A screenshot is here: https://imgur.com/UkJC88g

* All 3 photos were taken and added to my library in late 2016 or early 2017

* All 3 photos are JPEG format (file extension JPG).

* Since these are old photos, it is quite possible that I used a (much) older version of Photos, or iPhotos, or Aperture to edit them in the past.

* For one of the photos I did a "Revert to Original" and then tried to export again. The revert operation worked, but it did not help: subsequent export attempts still failed with the same "Unknown Error (4)" on the new MacBook.

* Also likely unrelated to the issue at hand: yesterday I enhanced a few hundred photos trying to reproduce another issue (namely https://discussions.apple.com/thread/251652645). Since then (until I rebooted my MacBook in safe mode today) the photolibraryd daemon was pegged at 100% continuously.

Per the suggestion of Apple tech support I have repaired the photos library. The repair itself took about 5 hours. For the past 24 hours or so photos is in the process of "Restoring from iCloud...". It will probably takes several days (or more) to complete.

So far, the issue has not been fixed: I still get the following errors:

• Duplicate photo: Failed to download assets for duplication
• Edit photo: Cannot Start Editing, Photos cannot load adjustments for this image.
• Export photo: Error = Unknown Error (4)

I will report again once the "Restoring from iCloud..." is complete (although I do not expect a difference).

Hi Old Toad,

Thank you very much for looking into this and for your suggestion.

Yes, I do still have the old laptop with a photo library, but unfortunately copying the photo library from the old laptop to the new laptop is not a solution in my particular situation because I have had the new laptop for several weeks already and I have already added thousands of new photos on the new laptop.

Hello Joseph_S,

I managed to reproduce the "Export Unknown Error (4)" issue.

A screenshot of the actual error message is here: https://imgur.com/Ob3cqLZ

On my new MacBook 2020, exporting this particular photo consistently fails.

Both "Export" and "Export Unmodified Original" fails.

The error message appears immediately when I click the Export button in the Export dialog (there is no delay at all).

The error is consistent for this particular photo: it fails every single time I attempt to export.

I tried quitting Photos, restarting my MacBook, restarting Photos, and exporting the same photo again: it still fails with the same error (4).

This photo was taken in 2016, which is somewhat early in my library (the photos range from 2012 to 2020).

It appears that the majority of other photos in the library don't have the issue - I had to try about 30 photos before I found one that failed. (I had to search because I forgot which photo had the issue when I first reported the issue.) Still, if Photos "loses" 3% (1 in 30) of my photos, that would be quite a disaster.

When I log into iCloud using a web browser and locate that particular photo "in the cloud", the photo was there and I was able to download it from iCloud. I did notice, however, that my albums were in a different order on iCloud than in my local Photos library (yes, I care about the order).

One interesting observation: the error dialog contains a "Reveal in Finder" button. When I click that button, the dialog closes, both nothing else happens: no file is revealed in any finder window.

When I export the exact same photo on my old MacBook 2016, it exports fine without any errors.

Update: it appears that many more than 3% of the photos are affected.

It appears that the majority (but not all) of my photos from mid-2016 until mid-2017 (possibly more) are affected on my new MacBook: thousands or tens of thousands of photos.

I tried a (very small) random sample of those photos on my old MacBook, and there they can still be exported without a problem.

I also noticed that my old MacBook is still being synced with iCloud: any new photos that I add on my new book auto-magically appear on my old MacBook (although the albums are in the wrong order, as mentioned earlier)

@leonie: Per your suggestion, I unsuccessfully tried adding Photos to the "Files and Folders" permission list:

* I unlocked the padlock

* Photos is not in the list, so there is no checkbox to check

* The +/- icon is grayed out, so I cannot add Photos

I did add Photos to the "Full Disk Access" permission list:

* I unlocked the padlock

* Photos was not already in the list

* I clicked on the + icon (this time it was not grayed out) selected Photos from the Applications folder

* When asked "Photos will not have full disk access until it is quit" I selected "Quit Now"

After this, I tried exporting the problematic photos again:

* I still got an "Unknown Error (4)" error when attempting to export the photos

* I still got an "Cannot Start Editing - Photos cannot load adjustments for this image" error when I attempted to edit the photo.

Since giving full disk access to Photos did not resolve the issue, I removed the full disk access again after this experiment.

Thanks for the tip on fixing the permissions on my Home Folder. Since I don't have any of the issues in the linked article, I will not do anything on this front right now (don't fix it if if ain't broke mentality), but I will keep it in mind for if I ever run into those kinds of issues.

PS: I did have massive file permission issues when I tried to restore files from a very old pre-Mojave time machine backup, but that is a story for a different thread.... I really wish the Apple engineers focused more on fixing existing bugs and making the system more stable rather than adding more and more unneeded features that increase instability.