Already discussed here:http://www.fsdreamteam.com/forum/index.php?topic=2284.0
It's an antivirus problem. The usual suggestion is always this, please follow it exactly, don't skip any step:
- Uninstall the scenery. Reply YES when asked if you want to remove the Addon Manager and the Couatl Engine. Reply YES to both questions.
- TURN OFF your antivirus. Don't just exit from its interface, but turn off the real time protection. Actual wording changes between products, however, it's the option to scan every file that gets open in real time, without user intervention.
- Reinstall the scenery with the Antivirus TURNED OFF. Don't launch FSX yet.
- Configure the antivirus to exclude the following files from scanning:
YourFSXFolder it's usually C:\Program Files\Microsoft Games\Microsoft Flight Simulator X, if you installed it in the default folder.
- Now you can turn the antivirus back on, and launch FSX.