Copying and restoring 4TB Photos Library from one external hard drive to another

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Level 1

4 points

Copying and restoring 4TB Photos Library from one external hard drive to another

I have my photos library on an external hard drive (photo library is 4TB) and it constantly keeps updating and restoring but I dont know why and its every time I open it. Its not the most up to date version but I was to worried I'd loose my photos to update it without a back up. It's my entire life and work on it so I have been pushing it back until now.

I have just bought 16TB drives to make a copy on it so there is no chance I will loose anything. I now need to make a copy onto the 16TB hard drive but when I had originally copied and pasted it, it wouldn't open at all on the 16TB drive it took 2 days to copy.

I don't know how to copy it over and get it to open without updating or restoring or not working entirely. I have tried disk utility but it says no issues every time. I dont know there is a corrupt file in the original photo library that is causing the issues either. If it would open straight away that would be great but I know thats a long shot currently.

I was going to try and copy it to the 16TB drive then update one of the versions to see if that works better but didn't want to until I defiantly have a copy of the photo library.

There is nothing on either drives (apart from the one with the original photo library on) they are both formatted the same - Mac OS Extended (Journaled)

Any help would be amazing!!!!

[Re-Titled by Moderator]

Original Title: photos on an external hard drive to copy onto another external hard drive but it keeps having to restore

MacBook Pro 13″, macOS 14.1

Posted on Aug 5, 2025 05:50 AM

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Answer 1

Aug 5, 2025 08:24 AM in response to AL_1789

I'm not sure what we can do without seeing the stuff. The "Mac OS Extended (Journaled)" format should work. Are these spinning mechanical drives, or are they SSDs? I they are solid state drives, APFS would be better. That doesn't say anything about your problem, though.

2 days to transfer 4TB seems kind of out there. I'm pretty sure that the SSDs I have would do that in well under 2 hours. Do these use USBc cables? It turns out that some USBc cables are meant only as power cables, and the are worthless for transmitting data. Are you sure of the cables? Use the free app Black Magic Speed Test to see what the transfer rate is. You should expect over 150 MB/s from a spinning drive, and maybe 700 MB/s or more from an SSD.

You should try transferring smaller files to see if that works. You're starting with the hard stuff.

Let us know what you find…

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Answer 2

AL_1789 Author

Level 1

4 points

Aug 7, 2025 02:53 AM in response to Richard.Taylor

Hi Richard.

The hard drive with the photo library on is a T7 shield and the new hard drive is a seagate expansion 16TB that I am transferring everything to (not an ssd). The new hard drive is quick at downloading, it's done everything else that I have tried to transfer really quickly just not this photo library. The cables are both USB, they are the ones that came with both hard drives. Thanks I will do a speed test to check.

Is it better to open up a new library on the new hard drive and transfer photos from one library to another that way? Due to so many files I dont know why I doesn't open first time but could it be a corrupt file in the photo library causing it to update and restore every time?

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Answer 3

léonie

Level 10

199,927 points

Aug 7, 2025 05:53 AM in response to AL_1789

Have you set the "Ignore ownership on this volume" flag on your new drive?

If you cannot set this flag, there is probably a problem with the new drive. For example, if you are using the new drive for other backups as well. A Photos Library must not be on a volume that is used forTime Machine or other backups. See: Move your Photos library to save space on your Mac - Apple Support

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Answer 4

Aug 7, 2025 07:44 AM in response to AL_1789

When I looked up your "Samsung T7 Shield Portable SSD," (this is 4 TB, right?) it says 1000MB/s, which is normal. (Mine say 1000MB/s, also, and with my cables and ports I just checked and sawI speeds for about 850 MB/s.) So it would be good to check your speeds.

I drag Photos Libraries from drive to drive all the time, and I have not had a problem. If the 4TB is empty anyway, I would re-format it as APFS.

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Answer 5

AL_1789 Author

Level 1

4 points

Aug 7, 2025 11:30 PM in response to Richard.Taylor

I will check the speed thank you!

The T7 has the photo library on, which I can't reformat it until I know the library opens on another drive. But every time I've tried opening it on another drive it just sits on restoring for hours and doesn't open.

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Answer 6

Aug 8, 2025 04:55 AM in response to AL_1789

Some quick thoughts and shots in the dark.

So the 16 TB drive is a spinning HDD, right? How fast is -- a decent HDD should have sustained speed about 100-150 MB/s while a SATA SSD is 500 MB/s or faster via newer interface than SATA. Good to know it is a HDD formatted as MacOS Extended (APFS tends to get VERY slow on a HDD).

Does the T7 has any 3rd party disk utility installed? Usually that is not needed nor recommended -- formatting a SSD as APFS (GUID) case insensitive via Disk Utility is best. Also avoid 3rd party virus apps and "cleaners" that often corrupt the system.

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