DesktopSimulations wrote on Feb 26^th, 2014 at 3:14am:

PS: I don't know why there was no Captain_Sim.p721.sys.gau file after the first installation. But I don't think it was due my anti virus software since I always add the entire FSX folder as an exception because of potential issues like this and to prevent lower frame rates.

Some Anti Virus programs will target the installer because it is not run from the FSX folder.

For example, all my Captain Sim installers are saved in my FSX Bought/Captain Sim folder, so I also have the FSX Bought folder added to exceptions, it prevents my FSX payware addon installers from being scanned during installation. ;)