My company has been going through this same issue.  I was speaking with my IT person today regarding a different issue and told him since they upgraded a couple of my computers to Office 365Online that our Summarize Payroll in Excel feature will not work properly.  While he was correcting my other issue he went in and resolved this issue.  I wish I could tell you what he did, but it was so quick that I could not catch it all.  It took him all of possibly 15 minutes.  

Maybe if you contact an IT person they may know what he did.  If not, please feel free to contact Wendell Wilson Consulting, LLC in Richmond, KY to see if they can help you.  I really hope they can because this is truly frustrating.