I have a strange experience. Following list discussion a few weeks ago I have not had Anti Virus protection on the Mac. Up to now everything is fine. This morning I have 8 e-mail delivery failures for e-mails I did not send, each addressed to various names like Ted and Brent etc @ my own domain. None of those name/addresses exist. The only mail I did send on that server yesterday was in answer to a (apparently) legitimate request for info for classes I teach. They were returned with the 'reason' of being infected with worm Mytob.T-2 So is it time to invest in Intego AV? Or is this not something to worry about? Appreciate advice. Tony