Mail Delivery Issues when using OUTLOOK 2003 and OST File
 

One of our laptop users has got an interesting issue when trying to change
the mail delivery functionality to a local C drive PST.
In fact, OUTLOOK 2003 is connected on an exchange server
The user had wanted to use a PST because of the space limitations set by the
mailbox.
The issue here is that whenever setting up the local PST to manage incoming
and out going emails, no email goes in nor out.. It stays stuck immobilised...
The configuration has been reversed to the original state, where the mailbox
is used with an OST file for offline access
Would anyone know what would cause this problem?

Many thanks
Trevor M