Hi sawyer7
I'm not from Laminar Research, just a fellow simmer in the UK with a couple of basic questions:-
1. Presumably the Boeing 767 model you purchased is written for X-Plane 11 and not Prepar3d or FSX etc.?
2. Presumably also, it is written for the correct operating system i.e. MAC OS in your case and not Windows?
3. Is the 767 in the C:\X-Plane 11\Aircraft\Extra Aircraft folder?
If the answer to the above is YES, then I would take the 767 aircraft out of C:\X-Plane 11\Aircraft\Extra Aircraft folder and re-start X-Plane 11 just to make sure it opens properly without any other issues?
If X-Plane 11 opens OK, then close it again and try re-installing the 767 aircraft back into the C:\X-Plane 11\Aircraft\Extra Aircraft folder.
If X-Plane 11 fails or crashes again after that, then you should file a bug report to LR, along with a copy of your X-Plane 11 Log.txt file.
Hope this helps
Regards