I have, at last, sorted out RF on my system but it's been a struggle.
I'm afraid the timeline for my installation difficulties is somewhat confused. I tried a lot of things and installed in various locations. I have a separate SDD which, being faster, was where I tried the first install and succeeded as I thought after disconnecting my PC from the web and disabling McAfee. However, as soon as I re-enabled the AV s/w the Launcher failed as its target had been quarantined. I got RF9.5 running by directly accessing the .exe file (and creating a new shortcut) and, I agree it works well, but I couldn't updatethe s/w.
I managed to acquire the new s/w directly from the web (HH website or here? Not sure

) and, after disabling the AV was able to install it all and put it where it wanted (C: programs(64)) rather where I wanted it on my SDD. It all went swimmingly until I switched the AV back on and the link was quarantined. I'm not really familiar with how to configure McAfee but I found that by disabling it I couldn't select a file to put in the exceptions folder so I changed the settings so it didn't examine files. I was then able to select Launcher9.exe and RealFlight.exe (and anything else I could think of related to RealFlight including RealFlight_9.5_installer.exe, probably unnecessarily) and every thing now works.
As I stand right now, I removed all of RealFlight from my PC other than the update installer because there were files all over the place and I like my HD tidy and I like to know where my data are stored. I then restricted my AV s/w as above and re-loaded RF9.5 successfully as the current, up todate version. However, once the AV was switched back on the Launcher link was quarantined, so I had to go through the process of restoring it and putting it in the Exceptions' file. Now it all seems tidy, and is working.
What does annoy me is that this issue isn't highlighted and initially I thought I had a problem with my machine unconnected with RF so I spent a lot of time reconfiguring with a fairly recent Ststem Image back-up which was very tiresome. I knew nothing of this until I came here looking for answers - and got few. I've been retired over 25 years but I've been involved with electronics and eventually microprocessors all my life. I used to write a lot of assembler as embedded s/w for measuremnt and control systems so I'm not totally inexperienced. How a total IT novice would overcome this issue I don't know.
There is a full back cover advert for RF9.5 in the latest issue of the BMFA News (I'm British) which arrived about a week ago. This s/w should be withdrawn from sale until a user friendly solution is found or, at the very least, the potential difficulties should be highlighted. An honest company would do that. Look at the furore in the US over VWs emission issues and how car manufacturers treat problems for example.
I'd apologise for the rant but I'm afraid I think it's justified.
Geoff