I have six others that are working fine. It launches, I can see my previous import’s images come up, work for about 5 seconds and it’s frozen. I have renamed the catalog and launched it from the backup version and it does the same thing. I have also resent Lightroom preferences. I tried optimizing the catalog and it went about ¾ of the way through doing that and froze. Everything I've seen on forums seems to reference cases where all catalogs are freezing.