Try resetting to default preferences:
Move the preferences folder (found in the Output folder) to the desktop, then restart X‑Plane and default preferences will be restored. If the default preferences do not fix your problem, you can simply replace them with the folder you moved to the desktop and restore your personalized settings.
If defaults does fix the crashing, you can send a .zip copy of the old problematic preferences to the bug reporter for investigation. Include a log.txt from a crash and the full Apple crash report. (Copies of the crash report are in Username/Library/Logs/DiagnosticReports/ . You may have to show hidden folders. They will be named after the app and the date and will end in .crash.)