Outlook mailbox name not updating
hen using Microsoft Outlook client to access Exchange mailboxes and Inbox, the Outlook does not actually update the all mailboxes and Inbox folder.The content and emails in the mailboxes are not refreshed, i.e.
You'll notice that you cannot change the user name field in Office 365 and the display shows, "This user is synchronized with your local Active Directory.
Some details can be edited only through your local Active Directory." You can change the UPN in AD, but it will not update the user name in Office 365 when Dir Sync runs.
But user can login to OWA (Outlook Web Access) or to continue to access the missing email messages, appointments, contacts, tasks, journal entries, notes, posted items, and documents.
The problem is likely to be caused by corrupted OST files, and various other reasons.
Here we can see mailbox users assigned with @email addresses.