LRc won"t open my catalog

I downloaded the latest LRc (may 9th). Now it won't open my catalog, telling me it already being used (it's not). I uninstalled and reinstalled LRc. Shut down, restarted the mac. No joy. 

Everything was working fine before the LRc update. Really frustrating.

MacBook Pro M3 pro

up to date Sequoia 15.4.1

LRc 14.3.1

I uploaded the message I get