Mail hangs when it receives a report that an e-mail could not be delivered.

Question

Hi Guys :o),
One bug which is really bugging me is that every time I receive a bounced e-mail report, with a subject line containing words to the effect of:
"Undeliverable. Return to sender."
or:
"The message could not be delivered."
Mail is unable to pull any subsequent e-mails down from the POP server.
So I junk the report, and then I delete it.
However, lo and behold, the errant e-mail is INSTANTLY back in my Inbox, plus there's now AT LEAST one copy in my Mail Junk, and also AT LEAST one copy in my Mail Trash.
Round and round I go, junk, delete, junk, delete, but the errant e-mail refuses to go away, and Mail continues to be unable to pull any new e-mails down from the POP server.
Eventually, Mail just hangs, with a spinning disk.
Even a force quit and relaunch of Mail doesn't resolve the spinning disk.
The errant message just sits there, REFUSING to be deleted.
The only way to get round this bug is for me to go up to my POP server, delete the report, and then PURGE DELETE the report - on the POP server !
I then have to go in to my Mac, and go:
--> Users --> Home --> Library --> Mail --> Account --> Inbox, Junk, and Deleted
and then manually drag ALL copies of the report into the trash on the Desktop.
It happens so often (pretty much every day) that I've had to create a shortcut in my Dock which leads straight to the Account folder.
Mail has always been buggy under ALL versions of OS X, but this ongoing bug drives me crazy, mainly because there's NO logical reason for it.
Just because I receive an e-mail message from the Hotmail server, for example, which says that my e-mail could not be delivered, usually because the recipient's inbox is full, or because no such address exists, on paper, that's just another e-mail which Mail is pulling down from the POP server.
However, EVERY TIME I receive such a report, Mail hangs.
I'm reluctant to rebuild my Mailboxes, in case I lose any messages, but I will if you advise it.
Any workaround would be gratefully received.
With best wishes to everyone in the Apple community, especially those on the Infinity Loop.
In particular, I wish Mr Jobs a very speedy recovery.
Cool,
Michael T
London, England

Answer 1

Quit Mail, Right click on that Mail folder, choose archive, you'll get everything in the folder, and the folder itself in a file called Mail.zip, move it to a safe place, same for the Mail Downloads folder... only the plist is separate.
/Users/YourUserName/Library/Preferences/com.apple.mail.plist
Not certain, but this can fix myriad Mail problems...
Safe Boot from the HD, (holding Shift key down at bootup), it will try to repair your Disk Directory while the spinning radian is happening, so let it go, run Disk Utility in Applications>Utilities, then highlight your drive, click on Repair Permissions, then move these folder & file to the Desktop.
Move this Folder to the Desktop...
/Users/YourUserName/Library/Caches/Mail/
Move this file to the Desktop...
/Users/YourUserName/Library/Mail/Envelope Index
Reboot.
If that doesn't do it and you can afford to redo all your Rules, try these & reboot...
/Users/YourUserName/Library/Mail/MessageRules.plist
/Users/YourUserName/Library/Mail/MessageRules.plist.backup