As usual, the antivirus it's at fault. We sent the Couatl.exe to ESET to report a false positive about a couple of weeks ago, they never care to even reply...
As explained many times already in the forum, whenever you get a virus alert, it's always the antivirus at fault: we digitally sign all our executables, so you can be sure they are not infected, because the signature guarantee that the version you downloaded it's the same we posted and hasn't been corrupted.
The solutions is always the same as explained in many other threads:
- Turn the antivirus entirely OFF during DOWNLOAD and INSTALLATION
- Before turning it back on, configure it to exclude the following files from scanning:
YourFSXFolder\bglmanx.dll
YourFSXFolder\fsdreamteam\Couatl\Couatl.exe
Then you can turn it back on and launch FSX normally.
The actual process of how to exclude files from scanning depends on your antivirus so, refer to its documentation how to do it.