Email Question

EMAIL QUESTION….I turn to the hivemind of the blogosphere for help. I have a weird email problem.

This morning, for the third time in a week, my email client (Thunderbird 2.0) was filled with identical pieces of spam. Same text, same sender, same timestamp. They pop into my inbox about once every ten minutes.

The first time this happened I thought I was the victim of some moronic spammer who had decided to send me a thousand copies of the exact same message. But then it happened again. And then a third time. Different spammers each time. And when I check my webmail interface, there’s only one copy of the email.

So it looks like the fault is Thunderbird’s. Every once in a while, it goes crazy and starts creating copies of emails. I’ve now figured out that if I go into the webmail interface and remove the offending email from the server and delete all the copies in my inbox and empty the trash, the spawning cycle stops. But I’m still curious about what’s going on. Anyone have any ideas?