Was exploring WM in Mint 19 Mate and totally messed up my system. The original Wm and more are missing. Control panel is missing, and some others appps don't work. Tried to fix with rescue mode using the 'dpkg' selection and got error saying "An upgrade from tara to bionic is not supported with this tool". Ran system info selection and info says LVM State: Physical Volumes: not ok (BAD), Volume Groups ok (good). Also ran Fsck from live disk and it said it was clean. Tried to repair using gpart and couldn't access file system?
What is the best way to repair or rescue this mess. Just re-install or how should I go about it?
Paul

Do you have TimeShift running? If so, roll back to a snapshot taken before you started messing with the window manager.

Thank you Hydrurga so much. That solved the problem as far as I can tell. Forgot that was available, still learning.

No problem. I'm glad you were able to rewind as from your description a fresh install would have probably been the best option if you hadn't.