Fair enough. This occurs roughly once in two months when I least expect it.

But the point is that with just a bit more attention to detail, they could have made this process utterly unobtrusive: don't process more than once file per second, if you want want to build in heuristics to infer the disk seek bandwidth.

Btw, Microsoft Security Essentials may be doing things like this. For me, it is totally not noticeable.