I was setting an offset to a waypoint in the MCDU and immediately I entered a distance (5L in this case) FSX crashed to the desktop with the following error.
Axe CoRte Editor
FMGS.ini not found in<
Program will be terminated!
I think I may have solved this, it was the company route editor needed an upgrade to load. I have not tried the MCDU again but will in the next few days, I assume the MCDU was trying to edit the route somehow using CoRte editor and could not load it. Thought I would post in case anyone else has the same issue.