Norton was the first company I know to exclude known good files from on-access scanning. Now, AVG has the same feature...why haven't other makers caught on to this...is there a security issue involved? I would at least like to have the option. I think Avast now has a similar setup. Also, does MSE have anything similar? On my machine, the on access speed is best with Avast, then Avira, and then MSE.