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Why won’t a Photos library on an external drive open?

By Kayabyte · Last updated 3 November 2026

Short answer: usually the drive is not set up the way Photos needs, or Photos is not being told which library to use. Apple asks for a drive formatted APFS or Mac OS Extended (Journaled), not used for Time Machine, with “Ignore ownership on this volume” turned on. Quit Photos, hold Option while opening it, and choose the library. If it still fails, copy the library to a correctly formatted drive and try the copy.

Work through these in order. All of them are free, and none of them needs an app from us. Before you change anything on a library you care about, make a copy of it if you have the room.

Step 1: Tell Photos which library to open

Photos opens the last library it used, not the one you plugged in. According to Apple’s guide:

  1. Connect the drive and wait for it to appear in Finder.
  2. Quit Photos.
  3. Hold Option and click Photos. Keep holding until the Choose Library window appears.
  4. Select the library, or click Other Library to find it on the drive, then click Choose Library.

Double-clicking the library in Finder also opens it.

Photos shows an empty library? Apple says that if the drive is not available, Photos stops using the library on it and makes a new empty one in your Pictures folder. Your photos are not gone. Connect the drive and choose the library again as above.

Step 2: Check the drive format

Select the drive in Finder and choose File, Get Info. Next to Format, look for APFS or Mac OS Extended (Journaled). Apple’s page asks for one of those two, and also says:

exFAT or another format? That is outside what Apple asks for, and Apple’s forum helpers often name it as the cause. In our own test on macOS 26.6.2, real Photos did open a copy on exFAT without complaint, so a library on exFAT may open. We would still move it. Copy it to an APFS drive and use the copy.

Step 3: Turn on Ignore ownership

From the same Apple page:

  1. Select the drive in Finder and choose File, Get Info.
  2. Open Sharing & Permissions. Click the lock if you need to.
  3. Turn on Ignore ownership on this volume.

If the checkbox is missing or can’t be selected, Apple says the drive may not be formatted correctly, or was used for Time Machine without being erased.

Step 4: Read-only and encrypted drives

Step 5: Copy it and try the copy

A copy on a good drive rules out the old drive. Quit Photos, drag the library to a correctly formatted drive, and open the copy with Option held down. People on Apple’s forums report that this cleared errors such as 4302 and 5416 for some, though one thread about error 5416, which started after a forced eject, ended without a confirmed fix. Apple’s repair pages do not explain these numbers, and we can’t tell you what each one means.

If copying itself fails with read errors, the drive may be failing. Stop using it for anything else and copy what you can first.

Step 6: Try the repair tool

Back up first, then quit Photos, hold Option and Command while you open it, and click Repair. See Apple’s repair page. Apple’s page does not say how to aim the tool at a library on a drive, and we have no tested way to do it, so don’t assume it will repair the library on the drive. If repair fails, read what to do when a library could not be opened.

Where AlbumRescue adds something

If Photos opens the library, you don’t need us. AlbumRescue is useful when Photos won’t open it, or you don’t want Photos to touch it. Opening a library in Photos can change it. AlbumRescue only reads, and it also reads exFAT, read-only volumes and volumes with ownership ignored. In our tests the albums, captions, keywords and favourites it read from APFS, encrypted APFS, HFS+ and exFAT copies were identical to the live library.

What it can’t do: it can’t fix the library or make Photos open it, it can’t put albums back into Photos, and it can’t get originals that stayed in iCloud.

Steps with AlbumRescue

  1. Open AlbumRescue and connect the drive. Without Full Disk Access you can still choose a library on an external drive.
  2. Click the library in the list, or Choose a Library, then click Scan. Nothing on the drive is changed.
  3. Read Overview and Before you pay. They say how many originals are really on the drive.
  4. Choose Export for a free sample of 10 photos, in folders named after your albums, with sidecar files. Check them before you pay anything.

The scan, lists, comparison and 10 saved photos are free. The full export is USD 34 once, for 2 Macs.

Download AlbumRescue and scan for free. macOS 15 or later.

Questions

Can a Photos library be on an exFAT drive? Apple asks for APFS or Mac OS Extended (Journaled). In one test of ours Photos opened a copy on exFAT, but that is not something Apple promises, so copy it to APFS for regular use.

Why does Photos show an empty library when my library is on a drive? Apple says that if the drive isn’t available, Photos stops using that library and makes a new empty one. Connect the drive, quit Photos, hold Option while opening it, and choose your library.

Can my Time Machine disk also hold my Photos library? No. Apple says you can’t store a library on a device used for Time Machine backups.

What do errors 4302, 3142 or 5416 mean? Apple’s repair pages do not explain them, and we don’t know of a reliable meaning per number. Work through the steps above and try a copy on a good drive.

How do I repair a Photos library on an external drive? Back it up, quit Photos, then hold Option and Command while opening Photos and click Repair. Apple’s page does not say how to pick a library on a drive, and we have not tested a way.

Apple, Mac, macOS, iCloud and Time Machine are trademarks of Apple Inc. AlbumRescue is made by Kayabyte and is not affiliated with or endorsed by Apple.