Llh123

Level 1 (4 points)

Moving Photos System Library to new external drive to avoid long iCloud sync

Hi,

I have a 1.5 TB system photo library on an external drive. I want to move it to a larger drive. I have all my full size photos in iCloud and downloaded to this system photo library. It took a long time for iCloud to sync/check duplicates/search when I originally moved this library from the hard drive to the external drive 3 years ago (over 5 days). I'd like to avoid that long process if possible.

I have already copied the 1.5 TB system photo library to the new drive with, with the new drive having a new name. I did check to see if I plugged just the new external drive in and opened iPhoto, and directed it to this photo library if it would recognize it as my system library, and sadly as expected it did not. If I remove the new external drive and put the old external drive with the original system Photo library back in, open photos, direct it to the original photo library, it opens and sees it as the system library. I closed it and removed it (all while off line, so not iCloud syncing happened). I'm wondering the best way to get the system photo library on the new external drive. I have a few ideas/questions and also looking for any other ideas:

if I rename the new drive with the same name as the old external drive, will the copied system iPhoto library be recognized by photos and avoid the download/duplicate picture sync, that I assume will now take well over a week? I could also re format the new external hard drive and start over with the same name as the old external hard drive and then copy again the original system iphoto library to the new hard drive with the same name for the hard drive. Or move the original file to the new external drive and put the copy on a back up drive. I'm not thinking this will work, and I am interested in any advice or warnings about trying it.
If I only have the new external hard drive connected, and in photos I select it to open the copied system photo library, and then under setting select the copied system library on the new external drive as the system photo library, what will happen? will it still take the week or longer and basically go through every photo to scan for dups and look for faces/dogs/ect, but I'll retain my current faces/edits/searched dogs/ect?
if i create a new system blank photo drive on the new external hard drive, and then under settings click make it the system photo library will that potentially be a quicker process, since no photos uploaded to iCloud, but just photos download and aded to the new blank system photo library? I sure long with so many photos, but maybe quicker? What are the disadvantages of this, like do I loose all folder or face/dog/search recognitions? What are the advantages?
any other options/suggestions to limit the time syncing for days with iCloud?
What if I get a new laptop, in like a year, will plugging the external hard drive with the system library on it that works with my current laptop, work with the new laptop as the system photo library without a new 7+ day sync/dup search with iCloud (or will I be looking to do this all over again if I get a new laptop and try to system library on an external drive? (hoping not!)

It is a scary process to go though. It was nerve racking 3 years ago, and I was really worried it wasn't working/couldn't always confirm progress - but it worked.

Thanks for any help or advice !

Posted on Oct 16, 2026 7:11 PM

9 replies

Richard.Taylor

Level 7 (25,466 points)

Oct 17, 2026 7:37 AM in response to Llh123

Llh123 wrote:

1. Hi, I'd like to avoid that long process if possible.

The very best thing to do is to start with a new, fresh, empty Library, designate it as the System Library, and let it fill from iCloud. It will do everything it needs to do; it will take a long time; it will be faster and produce better results than trying to use a new copy of the old Library.

did check to see if I plugged just the new external drive in and opened iPhoto, and directed it to this photo library if it would recognize it as my system library, and sadly as expected it did not.

That's not how the System Library works. You specify the System Library in Photos Settings>General

If "Use as System Library" is not grayed out, then click on it to make it the System Library.

See this:

Make a New System Library connected to iCloud - Apple Community

Richard.Taylor

Level 7 (25,466 points)

Oct 18, 2026 7:43 AM in response to Llh123

Llh123 wrote:

1. I think I will likely create a blank photo library on the new external drive, make it the system photo library and let iCloud load it. Do you know if I'll loose the face recognitions, or will I still have them from the iCloud download?

I think some few may be lost. You will need to wait maybe days for Photos to re-scan all the pictures. As far a faces go, I make sure that I have the face names listed in the Caption, and any name that has a People (or pet) album I also have a keyword for. That way, if face names are lost, I can collect them with a Smart Folder and quickly re-create them. See this:

Saving Face Names for Genealogy - Apple Community

2. I had gone to make the new system iPhone library that I copied to the new external drive the system library under settings/general. It wasn't greyed out, but when I clicked on it, it alerted me that after it would remove all the photos in it, and check/upload/look for duplicates with the iCloud library (not just accept it as the system library as I had hoped with no weeks of syncing with iCloud library).

If it's empty, that shouldn't be a problem. But connecting a picture holding Library forces Photos to compare all the pictures there with all the pictures at iCloud Photos. That can be laborious. Starting with an empty Library is way faster.

léonie

Level 10 (205,585 points)

Oct 21, 2026 1:41 PM in response to Llh123

"Do you know if I'll loose the face recognitions, or will I still have them from the iCloud download?"

Named faces are syncing with iCloud Photos but when I started over with aa new, empty library usually some of the named faces ghave been missing, mostly the faces that I had added manually by marking them with a faces circle. I second Richards suggestion to add the names separately. I am usually adding the names of the people also as keywords. That makes it easy to check for missing faces with a smart album with two rules combines with "match all", for example "match all: Person/Pet > is not > Tux" and "keyword > is > Tux".

That makes it easy to find the photos of a certain person, where the assigned fee has been lost.

markwmsn

Level 6 (17,427 points)

Oct 23, 2026 4:48 PM in response to Llh123

I went through this with a library about half the size of yours a while back, on both initially populating the library on a new Mac mini M4 Pro and rebuilding the same library on a late-model Intel iMac. Each took a long time, in fits and starts, not clearly correlated with any condition on my machines or local network.

Things that generally help that you may or may not have considered:

Prevent the Mac from sleeping for the duration of the download. Let the screen sleep instead.

Likewise, prevent the external drive from sleeping for the duration of the download. Depending on the model, that may be harder to figure out.

Obviously, try to keep major loads off your system and local network, but don't obsess about it.

Llh123 Author

Level 1 (4 points)

Oct 17, 2026 5:03 PM in response to Richard.Taylor

Hi!

Thanks! I think I will likely create a blank photo library on the new external drive, make it the system photo library and let iCloud load it. Do you know if I'll loose the face recognitions, or will I still have them from the iCloud download?
I had gone to make the new system iPhone library that I copied to the new external drive the system library under settings/general. It wasn't greyed out, but when I clicked on it, it alerted me that after it would remove all the photos in it, and check/upload/look for duplicates with the iCloud library (not just accept it as the system library as I had hoped with no weeks of syncing with iCloud library).

Thanks again!

Llh123 Author

Level 1 (4 points)

Oct 23, 2026 1:33 PM in response to Richard.Taylor

Hi!

I've started from a new blank library on my new external hard drive.

It took a week last time I did this, and I expect it to be even longer now that it is larger.

Observations/data:

It took only 2 hours to do the initial sync with iCloud to get the total number of files acknowledge, and start the thumbnails. Only like 1 percent of the photos (the most recent) have a thumbnail, and none have a full file. That got it to 14GB of the expected 1.5TB.

It then grew by .042 GB/hr hours 2-4).

Now 22 hours into it, it is up to 23GB and growing very slowly at .0004GB/hr now.

I've checked the wifi connection and have a good connection and upload and download speeds, and unlimited data on my plan.

At these rates, assuming it works, it will take months or more.

question:

Is it ok for me to close photos app and reopen it?

Could that speed it up?

I've been staying off it, hoping it would go faster, but I will not be able to stay off it for a month.

Is there a way to jumpstart it or to have it continue syncing or to speed it up?

I no longer see (for the last 18 hrs) cpu activity under activity monitor for Photos or photolibraryd or photoanalysisd, which were all active using 100% of CPU time for the first 3-4 hours when I had started. But now they have 0% CPU and very minimal increase in CPU time over the last 9 hours (40 min on photolibraryd and photoanalysisd each). Just checking if this is what others have experienced and if they are any suggestions to help it go faster.

Otherwise I'm just staying off the laptop, and being patient (but a little worried).

Thanks!

Yer_Man

Level 10 (166,900 points)

Oct 17, 2026 12:57 AM in response to Llh123

I'm afraid it will always notice the new location for the library and it will always check it.

Llh123 Author

Level 1 (4 points)

Oct 17, 2026 2:21 PM in response to Yer_Man

Thanks. I was afraid of that.

Thanks for the response and help.

Llh123 Author

Level 1 (4 points)

Oct 21, 2026 10:59 AM in response to Richard.Taylor

Hi!

Thank you so much for the info and responding.

Very Appreciated.

Originally posted at discussions.apple.com/thread/256377601