Photos library has fewer photos than expected after a migration or repair? How to find what is missing

By Kayabyte · Last updated 11 November 2026

Short answer: first make sure you are looking at the right library, because Photos can open a different or empty one. Then run Apple’s checks for missing photos, and find out whether the library only holds smaller copies. If photos are still missing, compare the old library with the new one item by item, rather than trusting the totals. Keep the old library untouched until you have done that.

Step 1: Are you in the right library?

Apple’s page on Photos libraries (checked 11 November 2026) says that if Photos cannot find a library on a drive that is not connected, it creates a new empty library at the default location, ~/Pictures. After a migration that looks like “everything is gone”, but the real library is usually still on the old drive or the old Mac.

Quit Photos, hold Option while you open it, and choose the library you meant. Apple says Photos then uses it until you open a different one. If you use iCloud Photos, Apple says to set the library you want as the System Photo Library. Opening a library can change it, so work on a copy of an old library. See how to open a Photos library from an old Mac.

Step 2: Apple’s own missing-photos checks

Apple’s page “If you’re missing photos or videos in the Photos app” (checked 11 November 2026) lists, in order:

Recently Deleted. Apple says you can recover a deleted photo from Recently Deleted for 30 days.
Hidden. Hidden items appear only in the Hidden album.
iCloud Photos. On a Mac open Photos, Photos, Settings, the iCloud tab, and check that iCloud Photos is selected.
Shared Library. Check the library view options.
Apple Account. Confirm you are signed in to iCloud with the same Apple Account on every device.

Step 3: Smaller copies, not missing photos

Apple’s page on optimising storage says Optimize Mac Storage stores smaller versions of your photos on the Mac when space is limited and keeps the full-size originals in iCloud. If this was on, a library on a drive or an old Mac can hold fewer or smaller files than the library you remember. To bring originals back, Apple says to choose Download Originals to this Mac in the iCloud settings of Photos.

A copy of the library that was made while originals were in iCloud cannot give those originals back, with Photos or with any app that reads the copy.

Step 4: Compare, don’t just count

If the checks do not explain the gap, find out exactly what differs. By hand, note the number of items in each album and for each year in both libraries and compare. That finds big gaps but not a handful of missing photos, and it says nothing about which ones.

A faster way: AlbumRescue

AlbumRescue is a Mac app we make. It reads a Photos library without opening or changing it, lists the albums and photos it finds, and compares one library with another: albums, folders and items that one has and the other does not, and those that differ. Usually that means the old library against today’s. It also has a Missing or Limited list that gives each item with no full original in the copy, with the reason, and it can save a CSV report that lists every item and every skipped item.

The scan, every list, the comparison and 5 saved photos are free, so you can see the gap before you pay.

Steps with AlbumRescue

Open AlbumRescue, allow Full Disk Access if you read a library on this Mac or in Time Machine, click Choose a Library and pick the old library (a copy is best), then click Scan.
Read the Overview, then open Missing or Limited to see items that have only a smaller copy, only a still picture of a video, or nothing here at all.
Open Compare and choose the other library. Read what the old one has that the new one does not.
If you want the missing items as files, choose Export. A folder is made with the original files, XMP sidecars and a CSV report.

The full export is USD 34 once, for 2 Macs, with one year of updates and a 30-day refund. Download AlbumRescue and scan for free. macOS 15 or later, Mac only, works offline and uploads nothing.

What it cannot do

It does not write into Photos, so albums and People do not go back into Photos through it.
It cannot get originals that are not in the copy, for example ones that stayed in iCloud. It never talks to iCloud.
Edits are not exported.
Shared albums, iPhoto libraries and libraries from macOS 10.14 or earlier are not supported.
Libraries from macOS older than 26 were tested only on synthetic test libraries, so an unusual older library could behave differently.

Questions

Why is my Photos library smaller than my old one? The two common reasons are that you opened a different library, or that Optimize Mac Storage kept the originals in iCloud. Check both before looking for loss.

Can I tell which photos are missing without opening the old library in Photos? Yes, AlbumRescue reads a private copy of the database and does not open the library, then compares it with another library.

Will the comparison change either library? No. It only reads.

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.