I'm running Lightroom 4 on a Mac v 10.15. When I launch it I get a "Problem Report for Lightroom" screen that says "Lightroom quit unexpectedly". I've tried the normal reboot. Anybody seen this? Thanks for your help.
It is unlikely that Lightroom 4 will run properly on OSX 10.13.5 (high Sierra). You might want to try rolling back your operating system to OSX 10.12 (Sierra), or purchasing Lightroom 6 (and applying the free update to 6.14) or Lightroom Classic CC