Photos library discrepancy after Mac OS upgrade

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Photos library discrepancy after Mac OS upgrade

I use the Photos application on my computer (iMac) and not much else. The Photos library is not synced with the cloud (this is intentional due to space constraints). I made a Time Machine backup of the computer in Sierra OS. I also noted that the Photos application held 46,100 photos and a few thousand videos (you can find this information by scrolling to the very bottom of the files shown in the Photos application). For additional reference, the size of the Photos library file shown in finder was 490 GB.

Then I upgraded the OS to Catalina. There was no error message. The Photos application in Catalina loaded just fine. But the Photos application now says it contains only 45,160 photos. It seems almost a thousand picture files were lost. Why?

The application indicates that it contains the same number of videos before and after the upgrade - no discrepancy there. Interestingly, the size of the Photos library file shown in finder is now larger at 503 GB. I am trying to understand why there is a discrepancy before I start using the application again...

Should I try to repair the library? This is my first OS upgrade and first time dealing with a Photos library issue. Is there a way to see what files are missing? There is no "recently deleted" folder showing up in Photos. I can't tell which pictures were lost. Trying to figure out if I should just live with the new normal or try to recover something valuable. Thanks!

iMac 27″, macOS 10.15

Posted on Dec 28, 2023 1:22 PM

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Answer 1

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fuji_crisp Author

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4 points

Jan 6, 2024 1:10 PM in response to fuji_crisp

For anyone else who may encounter this problem... I've spoken with Apple Support on two different occasions and here is what I learned.

Catalina is likely counting the photo files differently from my previous Sierra OS. For example, while working in Sierra the Photos application would count an original file as 1 and when I started editing that file it created a copy as 1 additional file (so, 2 total). Catalina, in contrast, counts them both as the same single file. This might explain my discrepancy but I think historically I've edited more than 1,000 files; as in I would expect to see an even larger discrepancy in Catalina. Still the best explanation so far...

Apple Support recommended a way to "check" to see what is missing. I can open the external disk used for Time Machine in Sierra, click/drag to copy the Photos Library file from my last Sierra backup and paste into another location (a different external drive in my case, because my desktop doesn't have enough room). Then, open that old library file in the new Catalina version of the Photos application - to help the computer recognize the library in the new OS. Next I would close Photos. Then reopen the application using my smaller Catalina library. Select "import" and import that old library file into the Catalina application. In theory it will show any missing items as "new" and ask if I want to include them in the Catalina library.

As an alternative fix, there was mention of overwriting my Catalina library with the old Sierra library file. Apple Support discouraged this approach.

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Answer 2

fuji_crisp Author

Level 1

4 points

Jan 13, 2024 9:51 AM in response to fuji_crisp

I copied the old Sierra Photos library file from my old Time Machine disk to a new external disk - took a long time, but it worked.

Then I opened the external copy of that library file in Photos on my machine now running Catalina OS. The computer automatically "updated" the file (took about an hour) and opened in Photos. This external/Sierra duplicate library shows in Photos that it contains 45,149 photos (even fewer than expected) and 2,137 videos (two more than expected?). The file on the external drive appears to have been modified and converted by Catalina.

So, the frustration continues. I want to resolve the discrepancy. Why the different numbers between libraries?

Here's a summary of my situation...

original Sierra Photos library contained 46,100 photos and 2,135 videos
new internal Catalina Photos library contains 45,160 photos and 2,135 videos
new external Catalina Photos library contains 45,149 photos and 2,137 videos

I think this means it can't just be a matter of how Catalina "counts" the files. Is something corrupted? What to do next?

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Photos library discrepancy after Mac OS upgrade

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