Combine two Photos Libraries

Thanks for reaching out, sphilipharris.

It looks like you were following the steps in Import photos from another library in Photos on Mac to merge two libraries. We can help.

You mentioned seeing the smaller library greyed out, and we wanted to make sure that enough time had passed for the merge to complete. If it hasn't, you may see one library greyed out until the merge finishes.

Let us know if there is any improvement.

What version of MacOS do you have.

The ability to import from another library only arrived with Monterey.

If you have an earlier version your options are more limited.

For earlier versions, your options are to export photos from one library, and then import them to the other. Or to use the paid app PowerPhotos from fat cat software which can move photos from one library to another (complete with edits) or merge libraries.