Addon Managers For
Flight Simulator
and Prepar3D

Addit! Pro For Flight Simulator X

The program takes a long time to load, 30 seconds or more, and performs slowly thereafter. What's causing this?

Virus scanning products

There appears to be a conflict between some virus scanning software and Addit! Pro. One culprit is McAfee's VirusScan/VShield version 3. VShield V3.1.x, when in memory, causes Addit! Pro and many other programs to load and run slowly. One way to solve the problem is to disable VShield. A better way is to upgrade to the latest version of VirusScan/VShield. Go to McAfee's web site ( to upgrade.

Another culprit is Norton's Anti-Virus. Try disabling Norton Auto Protect. If that doesn't help, update to the very latest version ( And if that doesn't help, disable Norton altogether.

If you use a different virus scanning product try disabling it and see if that improves performance.

Low Windows system resources

Another possible reason for poor performance is low system resources. No matter how much memory your PC has there are a finite number of Windows system resources. When resources run low applications begin to perform poorly and you will likely encounter other operating system problems. To check your resources, start Windows Explorer then pull down the Help menu. Your free resources are listed here as a   percentage. Clean systems typically have 85% or more free resource right after Windows first boots. Alternately, press the Start button click on Run and enter Msinfo32. Your free resources should be listed on the opening screen.

To free up Windows resources you must disable active programs. Press CONTROL-ALT-DEL to bring up the Windows task list. Use End Task to remove unneeded programs, especially Cleansweep and virus scanners. For Windows 98, the two to keep are Explorer and Systray. Windows XP users go to the Applications tab and use End Task on anything not essential; go to the Processes tab, sort by user name and use End Process on any User item that's not essential.