I'm using Windows 10, earlier my Lightroom was running fine, just now it show an error message and asked to reinstall the software.
After I uninstall and install again (after I active serial number from Adobe creative cloud), keep double click the Lightroom, it just doesn't start the application at all.
As I seen the forum said to remove "Lightroom Catalog.lrcat.lock", but still the same! Please Help!
Hold down the Alt key while launching the Lightroom, it will give the option to choose a catalog or create a new one.
Try creating a new catalog and check if that helps.