Following a major PC mod and upgrade, I've had a Jetline PC for about 5 years that has been upgraded to have separate SSDs: Win10/64 for P3DV4, and Win7/64 for FSX. When I purchased a separate RC4.3 for P3DV4, the older FSX version ceased to function with the following error:

"Component 'mscomctl.ocx' or one of its dependencies not correctly registered: a file is missing or invalid."

I "successfully" completed a process (from Google) to register the file; however RC would still not open (with or without as Admin.). Since both RC purchases were made from the same email, I'm assuming the newer version from September 2017 for P3DV4 has overridden the older 2012 purchase for FSX. In short, the P3DV4 version works without issue; the FSX version has the error above. 

My question is - Is the assumption correct as it relates to multiple registrations with the same email? Secondly, what can be done in this situation or is this a question solely for JD?

I suggest you write to Doug at [email protected] explaining the situation and ask for advice.

There can't be many people who are running RC4 for two simulations.

I will; thanks for the advice.