I too had blithely 'allowed' an auto update to LrC 10.1 v and never made the connection wrt that update and lockup on the application every time I used it - I'm not an everyday user...just once in a while.
After the 3rd time I came on here to discover the 'blow up'!! It's with this community I understood why!
I use a late 2015 iMac 5K Retina 27 inch, macOS Mojave 10.4.6
I tried a reco made on here to re-install previous version. So far...works like a charm.
I just wanna say while issues like this can be soooo frustrating I really do appreciate this 'community' as a problem-solver!