I ugraded Lightroom to v12 about a week ago. Had a photo shoot this weekend. Downloaded photos and edited. Yesterday LR began freezing, then crashes. Tried restarting LR - continues to freeze and then crash. I can't even open a photo or scroll through the Library. Went back to LR v11 and everything works fine, but it won't recognize LR catalog v12, and so I have no access to my recent photos. Did a new update to LR v12 - same result - freeze, then crash. Totally unusable. Using Windows 10. Top notch graphics card. Nothing else in "troubleshooting" helps.