I am also having this issue and I have gone through all of the steps listed above. I just installed a fresh version of windows 11. I installed Steam MSFS 2020. I installed all of the most revent VC++ distributable files and then attempted to install FSUIPC7 for MSFS 2020. When I start the installer and give permission for it to install, I get the Invalid OPCODE error. I am the only user on this computer and have full admin rights. I still cannot get the installer to work. I am hoping that you have another option/correction.
I have installed no other programs and have made no other modifications to windows 11. I am not able to get to any screens prior to this error popping up past the install permission screen. Your help is greatly appreciated.
R
Scott
