Exchange Server 5.5

Install the new server in the same site as the old server

Go into the old server and each mailbox property. change the perfered server to the new box.

The next time the user opens outlook it should automatically move the profile settings to the new server.

Good luck
cp

Personally I like the "forklift" upgrade procedure. In this procedure, you build a fresh Exchange server to the same version and service pack level but don't start the services until after you have transferred the database files from the old server. Although this is not the method preferred by Microsoft, they have published an article describing it (Knowledge Base article Q199954). This method has a further advantage in that the old server is entirely intact and if everything goes badly, youcan just plug it back it in and unplug the new one while you figure out what went wrong.

The alternative is to build the new server within the same site and use the Move Mailbox utility from within Exchange Administrator to transfer all the mailboxes. This is the method preferred by Microsoft, but I've had some difficulties getting the old server off-line without causing some disruptions (failing to re-home all the public folders, re-home all the connectors, etc.)

Either way will work, but I've had the best results from the forklift upgrade.

paul