For someone who is a regular Outlook user, when he tries to access the Outlook installed in his system, an error message saying, ”Cannot open your default email folders. The file xxxx.OST is not an offline folder file” may appear on screen. The presence of this error message maybe due to two reasons, Corruptions/problems with the .OST files on the system may be one of the reasons why the error message shows up. Another reason is that if the Microsoft Exchange mailbox cannot be accessed by Outlook, the error message may appear on screen. Sometimes in Outlook, you may not have set the correct settings for the Exchange mailbox in order for Outlook to access it. The email account or the Exchange mailbox for the Exchange mailbox in the Exchange server may be deleted or removed. Also, between the Exchange server and the Outlook, communication difficulties may be present. To fix the ‘cannot start Outlook’ problem, the below provided guidelines need to be followed. Instructions Th...