I guess the Title says it all. The source data is stored in Access. I update the data in Access monthly. I have pivot tables that have dates and those dates are grouped by Month and Year. When I refresh the pivot tables the dates all revert back to un-grouped date. Any idea why this is happening? I had this same problem last month and I thought it was because I received the dates in my data with time (mm/dd/yyyy hh:mm:ss). But I made sure that all the dates are actual short format dates (mm/dd/yyyy) and I am still getting the issue.

Thanks