Cannot create new folders or albums in Photo11 with Tahoe

There's not much to work with here. Can you give us a bit more information?

1. What model is your Mac?
2. What version of Tahoe are you running
3. Do you have more than one Photos Library?
4. 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?
5. Are you using iCloud Photos to synchronize your devices? If so
6. …Do you have “Optimize Storage” checked in Photos’ Settings
7. …Do you see all your Mac’s Photos  pictures at iCloud.com?
8. …Have you checked to see if the Apple Account is really really the same on the Mac and at iCloud.com?
9. …What is your storage at iCloud.com? At System Settings>[name]>iCloud>Storage , my Mac says 176 GB of 200 GB used. What does yours say?
10. What is your storage on this Mac? At System Settings>General> Storage, my Mac says 745 GB of 1TBB used. What does yours say?
11. Has this problem always existed, or did it just start? Can you think of anything that changed that might affect your device?
12. What does your Library say at the bottom of the Library view? Like this:

To narrow things down, try these steps:

• Restart the computer (of course)
• Re-start in Safe Mode. This bypasses certain potentially disruptive processes, and it often helps. Safe Mode is different for different computers, so see this: 

           Start up your Mac in safe mode - Apple Support 

• Use another library if you have one, or make a small test Library with a few pictures in it and see if the same thing happens. You can create a new Library by closing Photos and then option-clicking on the Photos icon.
• Make a new user and see if the same problem recurs with it.  This is a bit harder, because a new user can't access a different user's stuff. You would need to temporarily move your Library out of your own user's Pictures folder up to the general "Users" folder. 
• Rebuild your Photos Library--close Photos and re-launch by option-command-clicking the app icon. If you use iCloud Photos, it’s possible that this will cause a re-sync that lasts long enough to make you nervous. I usually turn off wifi when I do this.

The idea is to find out if the problem is with the Library, with your account, or with caches and login items, and stuff like that. One of these steps may fix the problem, but their failure to work also helps figure out what's happening.

Let us know what happens…