Photos library on external HDD issue

I've posted the same issue here: https://discussions.apple.com/thread/251028554?answerId=251948643022#251948643022

To me the issue raises when I designate the Photo Library as the system library.

I've searched for help to fix this issue, but haven't found yet in the community website.

Workaround is to log out.

But this is frustrating and un-Apple-like.

Open Activity Monitor and do a search in the CPU section of 'photo'. That will tell you which Photos subprocesses are running in the background. Post a screenshot of the Activity Monitor window.

How long has this been going on?

Do you have iCloud Library enabled with the library?

How big is the library?

Have you tried the Force Eject button? You may have to click on it more than once.

How is the EHD formatted?

How are you trying? what happens when you do? Any error messages?

What is the exact message?

Happy Birthday

Fu