I have a really hard time thinking this is server based when only one user has the issue.

Log on with another account on the same machine, and see if they have the same issues.

and try creating the user with the issues account on a nother machine and see if the issue can be recreated.

This will show if it is user accout\mailbox issue\ or machine issue. If it occurs with another account on the same machine...there is something on the machine interfering

if it occurs on another machine where outlook works fine...but user is still having the issue...then it is mailbox and server side.

MLF