After 10.4.9 Update I have duplicate mailboxes! Deleted one and lost mail!

Question

Hello,
Mail is giving me problems after the 10.4.9 update. I have duplicate mailboxes for each of my four accounts. After deleting the duplicate, I have lost all mail in that mailbox. It seems that although the mailboxes appear to be duplicates, they are not and deleting one deletes contents in the other. I'd like to know whether there is any way I could get back the mail I lost. Thank you in advance to those of you who could offer suggestions.

Answer 1

You’re welcome.
Yes, solving this problem will probably require re-creating com.apple.mail.plist. I’d like to know what the situation really is before proceeding, though.
How many accounts do you see in Mail > Preferences > Accounts and what type are they (POP, IMAP, .Mac)?
Report the names of the files and folders present at the first level of the ~/Library/Mail/ folder in the Finder.
In order to post the exact file names and avoid typing mistakes, proceed as follows. In the Finder, go to ~/Library/Mail/. With that folder open, if you’re looking at it in View > as List mode, first collapse any expanded folders so that the Finder only shows the files and folders at the first level of ~/Library/Mail/. Now, do Edit > Select All (⌘A), then Edit > Copy (⌘C), and paste it in your reply to this post.
Before actually posting that information, edit it so that the file/folder names do not reveal any details you should keep private, e.g. replace any real username with “username” to hide your real email address. Try to be consistent in how you disguise those details, though, as we may need to refer to them in subsequent posts.
Note: For those not familiarized with the ~/ notation, it refers to the user’s home folder, i.e. ~/Library is the Library folder within the user’s home folder.