And, just to provide a counter example: I always run Norton AntiVirus
with automatic / background scanning enabled. I generally have to,
because of infected machines at work which probe the network whenever we
get hit with the latest rash of viruses :(. I've done all my Cygwin
installs/updates with AntiVirus enabled and never had a BSOD (I'm running
NT4 on fairly stable hardware and up to date drivers). So, it is
possible and if something does fail, it more like a driver fault than an
application fault.