Photos Library size is different when on MacBook and then backed up to external drive

What format is your external drive? It needs to be APFS, or MacOS extended (Journaled), and needs to be directly connected (Not wifi or ethernet)

Most new drives come formatted EXFat - which is a windows format, and not suitable for a photos library.

See

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

Hi Tony,

I have the same issue - copied the Photos Library from iMac drive (1TB) to external drive and the Library has gone from approx 800GB to 1671GB. The external drive is formatted as Mac OS Extended (Journaled) - do I need to reformat this as APFS, or is something else going on? If I copy this back to the internal HDD will it fit??

Thanks,

Matt

Hi

No, you don't need to re-format, MacOS extended is fine.

Do you sync the library with iCloud? If so it is possible the library move has caused a complete resync of the library with iCloud. This can result in iCloud photos being downloaded to compare with the local library. If this is the case, then when the sync is complete, it should return to it's correct size. However, if that is what is going on, then for such a large library you can expect it to take a long time - weeks possibly.

What does the sync status say at the bottom of your all photos view? Here is mine (updated just now)

Tony - that makes sense, it is just saying "updating..." at the bottom.

Thanks for your help.

No problem - leave the mac on 24/7 connected to power with photos open. Just let it do its thing.