iCloud Photo Library doubled the size of my library when I moved to an external SSD

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iCloud Photo Library doubled the size of my library when I moved to an external SSD

Hi, all! There is another thread that is similar to this that was unfortunately closed, so I couldn't add to that one. Apologies for the duplicate.

I have used iCloud Photo Library for a couple of years now. The system photo library was in the normal default spot. I did NOT have optimization turned on: the library on the Mac contained all the full-res photos and video. I recently got an external SSD drive, intending to transfer my media (and my partner's media as well) to this new drive.

I copied the original Photos Library from my Mac. Its size is 148 GB. When I copied over the library to the external drive, it was still, of course, 148 GB. I pointed Photos to the new location, and it worked fine. When I went to test iPL from the new location, though, I found out that iPL requires that you use the SYSTEM photo library in Photos. It was easy enough to designate the new library as the System library...but when I turned on iPL the size of the new library immediately began to inflate...to over 280 GB. Close to TWICE the size!

Has anyone seen this behavior? The other thread suggested that this might be a temporary situation, but others that posted asking for an update didn't get an answer before the thread closed.

Thanks for any wisdom!

iMac 21.5″, macOS 11.4

Posted on Jun 25, 2021 11:38 AM

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Answer 1

Top-ranking reply

TonyCollinet

Level 7

23,954 points

Jun 25, 2021 11:40 PM in response to lkalliance

While it is updating, it may well have downloaded a copy from iCloud. It does this, so it can compare what is in iCloud with what is in your photo library.

If this is what it is doing then it will resolve once the sync is complete (as long as you have a compatible format for your external SSD - you did format it to APFS or MacOS extended before moving, didn't you?)

See

https://support.apple.com/en-gb/HT201517

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Answer 2

lkalliance Author

Level 1

40 points

Jun 25, 2021 11:43 AM in response to lkalliance

Followup, more info:

Though I expected the software to go through a process of comparing my "new" library to iPL, I didn't expect it to download a copy of everything. I don't know that it has, though: when looking through the library I do not see duplicates (though it is not finished yet, it still shows "Updating..."

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Answer 3

léonie

Level 10

197,303 points

Jun 26, 2021 1:57 AM in response to lkalliance

The size shown in the Finder for the original library may have been wrong. The recent versions are very slow at updating the size shown in the Finder. Sometimes the size will not be updated for weeks.

And Photos does not always automatically download all originals from iCloud, particularly, if you do not have much free storage on the volume.

To see, how large your library really is or should be, look at the size of the Photos Library in iCloud. Then add roughly 25% to the total seen in iCloud to allow for the size used for thumbnails and other working copies. How large is the library size shown in System preferences > iCloud > Manage: Photos? My library is showing there 184GB, and on the Macs it is showing roughly 230 GB. The local library should be noticeably larger than in iCloud, if all originals have been downloaded.

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Answer 4

lkalliance Author

Level 1

40 points

Jun 26, 2021 8:21 AM in response to TonyCollinet

The external SSD is formatted MacOS Extended. Thank goodness.

So late last night I double-checked the Photos Preferences and...I had it set to optimize storage! Gah! So I cancelled that (Photo Library size immediately reverted to 148 GB), and started again, hoping that was what was causing the issue. Nope. It immediately ballooned. So I went to bed, assuming that overnight it would have made some progress. It had. It probably finished growing to 280 GB, and then started dwindling. It had already dwindled down to 157 GB. Now it has finally finished, and the library file is back to 148 GB. Just took a while. I guess I figured it would compare without downloading the files...but now that I think about it you're right, that seems unlikely.

What was very interesting was watching the file size fluctuate down near the end. As I sat and watched, the file size didn't just go down but went up a step and a half and then down two steps. It might be at 150.00 GB, say, then slowly edge up to 150.15 GB, then suddenly drop to 149.50 GB. Very odd to watch. I'm sure there is a reason of course.

Anyway, it recently finished, and a test photo from my iPhone successfully arrived here at the Mac. Took roughly 12 hours (probably would have taken significantly less if I had better wifi strength).

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Answer 5

lkalliance Author

Level 1

40 points

Jun 26, 2021 8:25 AM in response to léonie

Hadn't thought about that, but it makes sense. On the size of the library file, I'd never thought to take a look at the storage in iCloud. There, the library was 126 GB, and down on the Mac it was 148. Your explanation makes sense.

When I first started the whole process up, I figured "Well, the library fits here on this partition, no worries!" but I got a dialog that said I couldn't turn iPL on because I didn't have enough room on the disk. Huh? But now I understand...it expects to (at least temporarily) need double the space to do the operation, which I didn't have left on the partition. So I moved some stuff off temporarily, which gave it the room it needed.

Thanks both of you for your help!

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iCloud Photo Library doubled the size of my library when I moved to an external SSD

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