How do I recover photos from an unresponsive Photos Library on Mac?

See if the free version of PowerPhotos view the Photos. It can view photos in a Photos library without opening it. If it works on your library the paid version will merge the Photos library into an empty new Photos library. The only thing you'll lose are smart albums (they come over as regular albums) and projects (also as regular albums).

It's also the most powerful utility for Photos Libraries there is.

Yes, pieces of the Library can be saved, including the original picture files. But you lose lots of information that you may have added, like edits, captions, titles, keywords, faces, and so on.

It can be hard to give advice with so little information-- can you tell us more?

• What model is your Mac? What macOS does it use?
• What exactly happens when you try to open Photos? What actions do you take; what buttons do you push; how does it respond; are there error messages?
• Where does your Mac's Photos Library reside-- in the Pictures folder of your internal drive, or on an external drive? or on a network? on iCloud drive?
• Are you using iCloud Photos to synchronize your devices? If so
• …Do you have “Optimize Storage” checked in Photos’ Settings
• …Do you see all your Mac’s Photos  pictures at iCloud.com?
• …Have you checked to see if the Apple Account is really really the same on the Mac and at iCloud.com?
• …Do you have more than 10% free storage on your iCloud account?
• What is your storage on this Mac? At System Settings>General> Storage, my Mac says 148 GB of 2 TBB used. What does yours say? Is your  free storage on your Mac less than 10%?
• Has this problem always existed, or did it just start? Can you think of anything that changed that might affect your device?

If we make guesses about these things, we may do more harm than good. So let us know…

Old Toad wrote: … See if the free version of PowerPhotos view the Photos. It can view photos in a Photos library without opening it.

That's a great idea! However, if the original is missing, and if that's the problem, then apparently PowerPhotos will not help. I tried it with a Library I have with some missing references, and I got this:

The "helpful" Report said this

That's why I suggested using PowerPhotos. It can view a library without opening it. If it works the Author can recover the library.

I didn't see where the Author said there were missing files, only that it was unresponsive and unable to open.

Old Toad wrote: …I didn't see where the Author said there were missing files, only that it was unresponsive and unable to open.

Exactly-- we don't know why it won't open.