How do I prevent drive ejection during Photos Library rebuild on my MacBook Pro?

Question

How do I prevent drive ejection during Photos Library rebuild on my MacBook Pro?

Folks, I am unable to successfully open and rebuild my Photos Library. Once the process starts, at a certain point (somewhere near 14%) the drive that the library is on gets ejected.

I used to run my library (about 354 GB in size) on a thunderbolt drive connected to a 2013 Mac Pro.
I tried to access that library from my M2 Max Mac over my home network.
M2 Max Mac has newer version of Photos.app. Not a problem. I have no issue with it attempting to update library. Full update did not complete since drive ejected. This is when problems started.
Connected drive with photo library to my M2 Max Mac directly in order to rebuild library. Rebuild fails due to drive being ejected.
Thinking there may be a drive issue, I tried to copy the library to an SSD. That fails too as the drive ends up getting ejected less than a quarter of the rebuild process
It seems any attempt to work with the Photos library in any way yields drives getting ejected. This doesn't happen in any other situation on any other drives and work I am doing.

I currently cannot open, view or work with the library since the drive won't stay mounted. Something about the Photo library triggers a drive ejection and I haven't been able to isolate how the application would trigger something like this.

Any thoughts?

[Re-Titled by Moderator]

Original Title: Can't Open or Rebuild Photos Library. Rebuild or Copy of Library Triggers Ejecting Drives.

MacBook Pro (M2 Max, 2023)

Posted on Jun 16, 2025 8:29 AM

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Answer 1

Top-ranking reply

Tangier Clarke1 Author

Level 2

306 points

Jun 16, 2025 5:53 PM in response to Tangier Clarke1

Happy to report that the library is restored. The only thing I did different this time is use the Amphetamine app to keep the drive from going to sleep. I didn't do this because I noticed that the drive was going to sleep. Instead I just remembered from experience that for some reason Apple silicon macs seem to have problems with different manufactured drives whereas the drives are continuously going to sleep. Not even the Terminal command "caffeinate" works....or at least it didn't for me.

It took about 3 hours for the 365 GB library to restore, but it is working just fine now and nothing seems to have been lost.

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Answer 2

Jun 16, 2025 8:53 AM in response to Tangier Clarke1

Tangier Clarke1 wrote:

2. I tried to access that library from my M2 Max Mac over my home network.

This may be where the problem started. A Photos Library cannot be run over a network-- it must be directly connected with a wire.

And how is your external drive formatted? To avoid damaging the Photos Library an external drive must be formatted in either APFS format or Mac OS Extended (Journaled) format. Additionally, the volume can not have had Time Machine on it since it was formatted. There have been so many problems with using incompatible drives that the newest macOSs won't even allow a Library on a non-Mac formatted drive to open, since there is a chance of damaging the Photos database. See this:

If this drive is in a an incompatible format, stop running Photos with it immediately! A Photos Library can sit on an incompatible drive, but running it may corrupt the database.

Let us know…

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Answer 3

Jun 17, 2025 4:45 AM in response to Tangier Clarke1

Tangier Clarke1 wrote:

It's currently connected to my M2 Max MBP using a thunderbolt to usb-c adapter through my CalDigit TS4 Thunderbolt dock.

If the drive is bus powered, then maybe it does not get enough power and ejects.

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Answer 4

Jun 16, 2025 2:45 PM in response to Richard.Taylor

Thanks for the reply Richard. The drive is a Raid 1 drive formatted as Mac OS Extended (Journaled). The drive hasn't had Time Machine on it since it was formatted.

It's currently connected to my M2 Max MBP using a thunderbolt to usb-c adapter through my CalDigit TS4 Thunderbolt dock. I also have the Amphetamine app running (as of this writing, it wasn't during the original post) to keep the drive awake since drives repeatedly sleeping on Apple Silicon Macs, particularly OWC RAIDs and some SSDs, have been a pervasive problem for me during video editing work.

By the way, realized I should have said "restoring" instead of rebuild since that's the word Photos.app actually uses; so as not to confuse anyone with some other unknown operation.

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Answer 5

Jun 17, 2025 8:38 AM in response to Matti Haveri

It was a fully powered (via a wall plug) Western Digital Raid. Though I'd think if it were bus powered, the OS would alert me when it's first plugged in that there's not enough power to support the device, or it would eject much earlier than it did. Otherwise that would mean that the bus power would have been fin up until it hit about 17% restore of the library, which would be odd for it to all of a sudden not have enough power. It took a good while to reach 17%.

It all works now though so I am pretty happy that nothing was lost.

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How do I prevent drive ejection during Photos Library rebuild on my MacBook Pro?

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