Office 365 Error – Cannot Start Microsoft Outlook–Quick Check

Upon launching Outlook and trying to connect to an Office 365 mailbox you may be greeted with an error message which states that “Cannot start Microsoft Outlook.  Cannot open the Outlook window.  The set of folders cannot be opened”.  The error then continues to state that ”Microsoft Exchange is not available.  Either there are network problems or the Exchange server is down for maintenance”. 

Cannot start Microsoft Outlook.  Cannot open the Outlook window.  The set of folders cannot be opened

You find this a little strange as the Internet is working, and there are no connectivity issues.  What do we do to troubleshoot this error?


Simple Things Are Important Things

Trying to log on with OWA yields a completely different error message.  It is actually a very good message since it states the problem and required resolution.

OWA Error message Is Different - The Issue Is Articulated

Oh yes, a license.  That would help matters! 

Looking at the details of the message the client is clearly told that there is a license issue and they need to consult with one of their IT administrators.  The expanded details pane is shown below:

OWA Error message Details Expanded


For those searching for the initial Outlook message, the search engines will allow them to discover the OWA details.

Hope this helps!



Rhoderick Milne [MSFT]

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