Nobody ever reported this problem so far. GSX will work from any folder, and where GSX is installed or where the simulator is installer, doesn't matter.
Since nobody ever reported this problem before, the only possible explanation is something specific in your system, try all the following:
- Uninstall GSX, reply YES to the question "Do you want to remove the Addon Manager ?"
- Reinstall GSX using only the current installer on our site. Don't install anything else, don't use an old download.
- Chose the default location, if you have enough space on C: If you don't, choose another drive but DO NOT install "inside" the P3D4 folder. If you want to install in D:, just choose D: and GSX will install into D:\Addon Manager, which is perfectly fine.
- Configure the antivirus to add the GSX install folder to its Exclusions. Add the simulator folder to the antivirus Exclusions too.