IMAP synchronization


I’m having a problem with my email I only just noticed. I have my Thunderbird client setup as IMAP to my mail server. Under Server Settings of the properties page I have the following settings checked off:

  • “Check for new messages”
  • "Check for new Messages every XXXX "
  • “Automatically download new messages”
  • “Leave message on server”
    ** “Until I delete them”

What I just noticed was that my client reports I have 50 or so odd messages. When I login via webmail I get a report of over 900 messages. As far as I can tell I have everything setup correctly to have my client synchronize with the server, but apparently that is not correct. I’ve clean out all my trash folders in my client and nothing has changed. Can anybody shed any light on this?