The name cannot be matched to a name in the address list for a valid user - Exchange 2010
In some cases, I hide old users in Exchange Management Console so they don't appear in the global address list. I had done that with a certain user, and I kept trying and trying to no avail to configure his Outlook. I kept getting "The name cannot be matched to a name in the address list for a valid user." I could log in to webmail for the user, and I could log on to a laptop as the user with no trouble - but Outlook could not find the user during mailbox setup/configuration.
The solution (uncheck "hide from Exchange address lists")