Do you have a backup from the last time you Quit LR when everything was working?
Restore a backup catalog
- Choose File > Open Catalog.
- Navigate to the location of your backed up catalog file.
- Select the backed up .lrcat file and click Open.
- (Optional) Copy the backed up catalog to the location of the original catalog to replace it. The default location is Pictures or My pictures.
Happens regardless of whether it is a existing or new catalog. Previews (Grid and Filmstripin ALL modules are grayed out.
Managed to get help from Adobe Chat. Agent discovered it was (is) a driver issue specific to nVidia based cards. Had to roll back to nVidia 350.12 as opposed to the latest which is 352.86. Once I rolled back, everything was back to normal.
Thanks for the effort!