[Merkava_4]

I'm not sending these e-mails; someone or something else is doing it.

[besson3c]

That is called Backscatter, and it is not a problem with Mac Mail.

I take it these messages are all spam?

[Merkava_4]

Yes sir it's all spam. What can I do to make it stop?

[besson3c]

Originally Posted by Merkava_4 

Yes sir it's all spam. What can I do to make it stop?

Nothing, really, beyond looking at the full headers of this and determining whether the person sending these was from a different IP address than your machine (as is most definitely the case). If the IP address is indeed different, there really isn't much you can do beyond possibly setting up a rule to move bounce messages from the Yahoo postmaster address elsewhere, but this would also affect legitimate bounce messages from Yahoo that might be of use to you, so I wouldn't recommend that.

Do you know how to access the full headers of a message? If so, feel free to copy and paste your message in here. You can replace your email address with something else for your privacy if you wish.

[Merkava_4]

I changed the password in my Yahoo mail account; hopefully that'll take care of the problem.

Thanks to all of you who have replied.

[besson3c]

Originally Posted by Merkava_4 

I changed the password in my Yahoo mail account; hopefully that'll take care of the problem.

Unfortunately that most likely won't accomplish a single thing. This is also fortunate in a way though, because if that were to accomplish anything that would mean that your account was compromised, which would be quite bad. The probability is exceedingly high that it wasn't.

[MacNNUK]

Set up rules in Mail preferences to delete these before appearing.

[besson3c]

Originally Posted by MacNNUK 

Set up rules in Mail preferences to delete these before appearing.

Although understand that, again, doing so will delete legitimate bounce messages from Yahoo too.