1 person found this helpful
How can we tell if you don't give any more details, like the version of MacOS X you are using, the version of Lightroom Classic, whether Lightroom Classic did run before or never did, any error dialogs you get? Saving a crash report and posting a link to it might also help the technical people on this forum to suggest a cause.
Try trashing the LR saved prefs and re-booting. Start by quitting Lightroom. Launch Finder and on the menu bar click “Go” whilst holding down the Optn(Alt) key and choose Library. Open the Preferences folder and trash the two plist files and any other .plist files relating to LR6 (see image below). It is also worth cleaning up any plist files relating to prior versions such as LR5 etc.
Then re-boot your Mac and re-launch Lightroom.
N.B. Apple hides the user Library until the Alt key is depressed.
Are you sure you are running LR Classic? Do you have a subscription or perpetual license?
Thanks a lot for this reply. Lightroom is workimg again, hurray!!!