A client who runs 2011 SBS has been having issues with their server ever since I migrated them to Office 365. Frankly I would prefer them to let me migrate back down to 2008 R2 standard or 2012 Standard but they want to hold off on that. In the meantime I have disabled most of the Exchange services they run on startup. Autodiscover is still keeping the event log busy. This is a good article I found to resolve this issue!