P: Most functions in Edit, Image, Layer, Select and Filter grayed out for image opened from LrC

Yes - disable Home Screen worked for me too.

Extremely strange but on very limited testing it also seems to work for me.  SOmething Adobe needs to be testing; Home Screen is new in PS v20 so this is probably what causes the problem.

Strange. But what also worked for me was, in Ps , in Preferences - General settings, select "Disable the Home Screen". I am guessing that it is something in the Home Screen causing the problem when Lr (or Br) launches Ps.

Peter

this workaround is not working for me. rebooted, opened PS before LR and still same issue, all greyed out.

Same problem for me in PS 20.0.1 opening from LR Classic CC v8.0; opening PS before LR seems to fix most but not all the time.  Going back to v7.5 also fixes it and another v8.0 bug (book module not saving changes).

If you select "edit in update, then s muted of problems show up you might experience problems such as quick keys missing, and missing, and all filters, adjustments gone. You must all ready have zps opened when you expo8 from light room, or save the photo, close ps, reopen ps and reopen folder. This sucks!!!!

Turns out even more is broken.  Skylum Aurora won't launch correctly either.  I ended up rolling back to PS 19.x.  All of my problems are solved.  I think I'll wait a while before I upgrade to 20.x.

I agree but on my system, I'm unable to run PS and Bridge another way (running Windows 10 1803 but it was also the case with previous versions). I have to run them as an administrator (not in any compatibility mode). This problem is lasting since years. Applying the various suggestions found in this forum, on the Adobe site  and elsewhere for fixing permissions never helped. PS and Bridge are the only programs forcing me to do this.

https://feedback.photoshop.com/photoshop_family/topics/ps-bridge-and-lightroom-still-need-to-be-run-...
https://feedback.photoshop.com/photoshop_family/topics/cc-apps-needing-administrator-rights
https://feedback.photoshop.com/photoshop_family/topics/bridge_will_only_run_in_administrative_mode
https://feedback.photoshop.com/photoshop_family/topics/many-ps-20-0-1-functions-missing-on-image-ope...

Still waiting for answers... During all these years I could observe that running PS and Bridge as an administrator is a way to solve many problems. I'm not alone with this issue. This is why I suggested trying this workaround.

If Ps and Lr require Windows 10 to run the things in compatibility mode, then Adobe has some 'splaining to do. I will also absolutely, positively never, ever even consider running the thing in administrator mode. In fact, I run it as a user without access to admin privs. You should, too.

Photoshop.exe and bridge.exe don't have a Compatibility tab in Properties

Instead of choosing Properties after right-clicking the .exe, select Troubleshoot Compatibility. Or you could have a look there :

https://www.laptopmag.com/articles/set-compatibility-mode-windows-10