We have a client that is now on Office 365. We migrated them from an in house exchange server 2010 to Office 365 back in April 2014 with no issues. Yesterday a user went to his calendar and saw that all his MANUAL entries from all of February 2014 and the past are missing but the reoccurring event entries are still there. All other users still have all there entries so this is isolated to one user.
We don't know when the entries have disappeared until the user searched for them yesterday. Is there a way we can get data from the old Exchange Server DB file and extract it for that user so we can import back to Office 365.
BTW check what the archiving/retention policy on that mailbox and the Calendar folder is (the default folder policy applies to Calendar since 2010 SP2: http://blogs.technet.com/b/exchange/archive/2012/08/14/calendar-and-tasks-retention-tag-support-in-exchange-2010-sp2-ru4.aspx), as the items might be moved/deleted by the policy instead.