Junk Mail filter can't handle high volume

Question

I use Mail.app at work/school. Unfortunately, my email address there is [email protected], and because it's so simple spammers have taken to sending spam that looks like it came from me. So every day I get dozens to hundreds of bounces from their spam, and my school's spam filter only catches about a quarter of them.
Here's my problem: 75% of the time, Mail catches all the spam bounces and puts them in my junk mail folder like it's supposed to. But if I get a whole lot at once - usually the first time I Get Mail for the day - it screws up and dumps them in the inbox. They're marked as Junk, but I still have to go through and delete them. The other day, I checked my mail and got over 200 messages in my inbox, only a handful of which were not spam!
If only a few - say, less than 20 - spams come at once, it works fine. But more than that and I have to delete them from my inbox. Anyone know how to fix this? I've played around with the JM filter settings.
(And if anyone knows how to make the spammers stop faking my address, that would be great, but I'm not hopeful.)

Answer 1

No, those folders could only be a problem if they existed and you had something installed there.
I’m not positive you’ll be able to find a satisfactory solution to this problem because, as I said in my first post, it’s not uncommon for Mail to choke on those bounces and the user not even being able to delete them by normal means, but you may try the following in case there is something amiss here.
Verify/repair the startup disk (not just permissions), as described here:
The Repair functions of Disk Utility: what's it all about?
After having fixed all the filesystem issues, if any, and ensuring that there’s enough space available on the startup disk (a few GB, plus the space needed to make a backup copy of the Mail folder), try this:
1. Quit Mail if it’s running.
2. In the Finder, go to ~/Library/Mail/. Make a backup copy of this folder, just in case something goes wrong, e.g. by dragging it to the Desktop while holding the Option (Alt) key down. This is where all your mail is locally stored.
3. Locate Envelope Index and move it to the Trash. If you see any other “Envelope Index”-named file there, delete it as well.
4. Move any “IMAP-”, “Mac-”, or “Exchange-” account folders to the Trash. Note that you can do this with IMAP-type accounts because they store mail on the server and Mail can easily re-create them. DON’T trash any “POP-” account folders, as that would cause all the mail stored there to be lost.
5. Open Mail. It will tell you that your mail needs to be “imported”. Click Continue and Mail will proceed to re-create Envelope Index — Mail says it’s “importing”, but it just re-creates the index if the mailboxes are already in Mail 2.x format.
6. As a side effect of having removed the IMAP account folders, those accounts may be in an “offline” state now. Do Mailbox > Go Online to bring them back online.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder. That is, ~/Library is the Library folder within the user’s home folder, i.e. /Users/username/Library.