Exchange 2010 Exchange Server name appears as Instance – <GUID>

Current Status: – no issue

Figure 11: Instance-GUID issue in 2003


The problem behavior can be triggered by networking , patch applications, server reboots, etc. It requires Outlook 2003 to lose connectivity to and have a delegate mailbox logon attempted on a connection before the primary mailbox logon is attempted on that connection. This can affect users who are accessing shared mailboxes or folders of other users from their Outlook 2003 while connecting to .

Currently there is no proper resolution available for this issue. However, to remediate this issue temporarily, simply re-resolve the Exchange server name in the Outlook mail profile. If possible, you may also remove the shared mailboxes or shared folders (like calendars) from the profile, preventing this issue from occurring in the future or create a new mail profile in Outlook.

is working to investigate this issue for a fix. You can contact Microsoft Support to report this issue and request further assistance. Currently no KB article exists for this issue.


Microsoft has confirmed this to be a and the bug was assigned to the Outlook team within Microsoft. It has been fixed and a hotfix can be downloaded here:


Special Thanks to Henrik Walther & Jaap Wesselius

Leave a Reply

Translate »
%d bloggers like this: