Lightroom CC 4.0 on MacOS Catalina 10.15.7 freezes after importing presets and attempting to navigate to the presets pane. The only rememdy is to force quit the application. I have already uninstalled (including preferences, etc) and reinstalled Lightroom, the presets reappeared automatically and the application froze immediatley on opening the presets pane.
After some more investigation it appears to be specfic presets that are freezing the application. If the carrot dropdown is not active, the application does not freeze. However, even uninstalling/reinstalling Lightroom failed to remove the imported presets.