Apologies for the slow response on this. The original issue from this thread was patched a long time ago, and FlyInside FSX should work for Windows 10. Could you shoot me an e-mail,
dan@flyinside-fsx.com to help me keep tabs on this?
To start:
1. Is it possible "Compatibility Mode" is turned on for FSX.exe?
2. Could you send me your Windows version number? Are you running Windows Insider builds?
Thanks,
Dan