Hi, Peter, As the e-mail indicated, that is correct and is currently the case. How this will play out down the road I am not entirely sure, but a definitive answer will be soon if not already depending on how forward goings progress. I wish I could be more concrete at the moment, and I do apologize for that. In short, the CRJ has moved to the clang compiler for 64-bit. While 10.6.x is 64-bit compatible as an operating system, it does not have the runtime for the clang compiler, and thus the CRJ as it stands right now will not run on this setup in 64-bit X-Plane.