We're sorry about the trouble with Lightroom. Would you mind telling us which macOS version are you working on? Have you tried re-installing the app to check if that helps? If not, please try that & let us know if it helps.
You can try resetting the Preferences of Lightroom by launching the app while pressing & holding the Shift + Options keys. When you get the prompt to confirm, press Yes/Reset Preferences to check if that helps.