Synchronizing Folders and Messages
If you are using IMAP with a desktop mail program, you could occasionally find that the list of messages and/or folders being presented in your mail client differs from what you expect to see, or from what you know is on the server.
The following instructions are methods for "resynchronizing" or "refreshing" your folder list in the more popular mail programs.
Mozilla Thunderbird: Within the mail program, choose File-Subscribe and click on the Refresh button. You should then make sure that there is a check mark next to each folder you want to see.
Entourage: Do a right click on the name of your IMAP account in the folder list to the left and choose Receive Complete Folder List.
OS X Mail: Go to the Mailbox menu and choose Synchronize (account name).
Outlook: Click once on the name of your IMAP account in the folder list to the left and do a right click on it. Then choose Update Folder List from the menu.
Outlook Express 6 for Windows: choose Tools->Synchronize All from the menu.
Outlook Express 5 for the Macintosh: Click once on the name of your IMAP account in the folder list to select it. Then click on the Update List button OR if that doesn't seem to help, do a control click on the account name and choose Empty Cache.