I'm 100% sure that it is caused by GSX.
No, it's not. GSX cannot possibly crash the sim, since it's an external .EXE and, external .EXEs, by definition, cannot crash another application, they simply don't have any access to it.
What might be happening, instead, could be:
- You have a corrupted .BGL file, so the sim its crashing because GSX is scanning that file when rebuilding the cache.
OR
- Your antivirus is interfering, making the sim crash (the antivirus can do that, because it's a Windows service) because it's trying to scan itself all files that are being opened by "anyone" so, when GSX is scanning the files looking for airports, the antivirus crashes the sim.
First, add the whole simulator folder from the antivirus scanning, and see if it makes any difference.