Sorry, meant to mention that. The machines we’re running currently are Windows XP. If it’s possible that Windows 7 provides better hooks for this we may need to test it (porting our application to Windows 7 is on the roadmap anyway) but I’m not very familiar with the Windows APIs.

Yeah, MSE had the same impact. Avast has actually had the smallest impact with Symantec products having the worst (avast puts us at around 18 minutes symantec at around 25).