There is a known Microsoft bug in some of the Outlook version installed on our systems.  

Microsoft 365 group users may be unable to view or access group calendars and email messages in Outlook Desktop - Microsoft Support 

From Microsoft

Final status: We've confirmed that the fix has reached all affected environments. Users will be prompted by the client to update their build to 16.0.16327.20214, which will resolve the problem.


If you are experiencing some of the following, you will need to update your Outlook client.

  • Outlook freezes when accessing calendar
  • You receive an error when trying to view the calendar
  • Access to shared Group calendar is intermittent


Update your Outlook client by following the steps below.  Alternatively, you can always access your calendar from OWA (Outlook Web Access) at  If you are still having trouble are need assistance updating the client, please open a support ticket at


The following can also be viewed on our support page knowledgebase located under “Solutions” at



Click File -> Office Account -> Update Options -> Update Now