Long-time LRC user here. I use three catalogs on my Windows 10 computer (5 years old). I'm running malwarebytes. LRC ver. 11.0.1.
I've had several corrupted catalogs since updating to ver. 11, and just now had another one with 11.0.1. It's happened to all three catalogs but at different times. I can use one but another one will be corrupted. When I use a backup catalog I can use it a number of time and it will get corrupted again. This is extreeeeemly frustrating as I put a lot of work into LRC. Earlier versions never did this.
It seems I can use a catalog at least four or five times before it again becomes unuseable and I get the "Unfortunately this catalog is unrecoverable..." error. Ugh... Help!
Corrupted catalogs are almost always caused by hard disk malfunctions. If you have an uncorrupted version of your catalog file, copy it to a different disk, open it from there, and see if things work better.