Question : How do I "leave a copy of messages on server" in exchange?

When my client downloads emails from his SBS2003 it remove the mail on the server, is there anyway in exchange to leave them on there as there is on a normal POP3 standalone client?

Answer : How do I "leave a copy of messages on server" in exchange?

In Exchange, there is only a setting for the delivery location.  If the delivery location is the server's inbox, then the message stays there until deleted.  If the location is set to a PST file, then messages will be moved (not copied) to the PST file when the user connects to the server.

If the user is on a LAN, then there is no need to use a PST file unless the user has tons of mail that exceeds their quota (in which case, they should be moving stuff into it manually instead of having the Exchange server deliver it there).

If the user is mobile and can't be connected to the server constantly just to read their e-mail, there is a third option.  It is called an Offline Storage file (OST).  This works exactly like synchronizing your blackberry or similar device.  A copy of the mailbox is kept on the local machine for offline use, and when the user connects to the server, a comparison is then done to see which items are new, which ones should be in the trash, etc.

To config it, open Outlook and go to Tools->E-Accounts.  Select the 2nd button from the top "View or change existing E-mail accounts"  Then hit Next.

Select the user's mail profile and hit the Change... button.

You should now be looking at the settings for the Exchange server.  Hit the More Settings... button.

From the dialog that appears, go to the Advanced tab and hit Offline Folder File Settings...

Configure yourself an OST file and hit OK to everything.

You have just configured an offline file.  This will copy down new messages to the user's laptop while maintaining a copy on the server in case they access it from another machine or OWA.