Ouch!! Mail program re-downloading all messages stored on server

Question

A couple of days ago, while going through the regular routine of checking email, my Mail program went into a wild beach ball spin and re-downloaded every single email message that was stored on the remote server again into my inbox. I use Mail to bring in messages from a few different accounts. The re-downloading of the messages occurred with sbc account email. Other accounts work as usual and did not behave this way.
Checked the settings on the sbc account both within the Mail app and at sbc and nothing indicated to make a choice to re-download messages from server when checking for mail. So, thinking this was just a fluke, and nothing to be overly concerned about, I just deleted the multiple messages out of the Mail app and went about business as usual. Yeh, you guessed it, only to find that the next time Mail went to retrieve from the sbc account the same thing happened all over again! YIKES!! (not fun deleting a couple thousand emails from your inbox) :s
Has anyone run into this happening with their Mail? Is it even possible *gasp* that I have actually encountered some type of spam virus??? I'm sorry I have to stop using Mail for the time being to retrieve and organize my email. Hope someone has some input that can help because using webmail, although it's safe, can be a real drag. BTW -- there has not been unusual activity in the webmail. No multiple messages. This is only happening when I'm retrieving mail using the Mail app locally.
Is it simply a matter of it being time to archive/delete... or anyone have similar circumstances that they can help shed some light here? Appreciate it y'all!! : )

Answer 1

I used to find this happening with older version of OSX after I did my usual 6 month clean, wipe, re-install and resume.
It's possible that the file which keeps a track of message downloaded from the server is corrupt. Goto ~/Library/Mail where "~" is your home folder and then delete these files
Envelope Index
LSMMap2
DefaultCounts
Next goto each account ".mbox"
This is in ~/Library/Mail then a folder which contains your email address example "Mac-steve.jobs"
inside there should be a folder list something similar to this:
Junk.imapmbox
Sent Messages.imapmbox
INBOX.imapmbox
Drafts.imapmbox
Deleted Messages.imapmbox
Inside each of them is a folder, called "Messages" and also some files, delete the files but not the "Messages" folder.
When you reopen Mail it will be as if you opened it for the first time. See if the emails come in, if they do then it's more likely to be a setting in Mail or even possibly something that's happening at the remote email server.
In Mail Right or Control Click in the left hand panel and select "Get Info" a box will come up with a drop down selection at the top showing active email accounts, select the one you are having problems with, either a list of folders will come up or a big long list of email messages, depending on how many you have will depend on how long it takes for the list to update. Once it has, select all the emails and Select "Remove From Server" this will delete them all from the server so at least when you re-open Mail they don't all come in again.
Hope something in here helps
Mark