SSRS 2014 URL access always generates XLS instead of XLSX when format is EXCEL

Question

I have SQL Server 2014 and I'm trying to access my reports via the URL access. As I understand, the Excel format should be giving me an XLSX file which supports an unlimited number of rows. However, after looking at my log files I noticed that I was getting maximum row errors for any reports with more then 65536 rows. After looking into this I discovered that any time I request the reports via URL with format as EXCEL, they generate a XLS file instead of XLSX. If I run the reports out of Visual Studio and export as EXCEL, they generate just fine as XLSX. Anyone have any idea how to fix this issue?

Answer 1

Found the solution to this problem so I figured I'd answer it here in case anyone else runs into this problem. the list of supported formats for URL access listed on Microsoft's website here shows the following list: HTML4.0, MHTML, IMAGE, EXCEL, WORD, CSV, PDF, XML, and NULL

It does not, however, list the one that actually generates an XLSX file. That format is EXCELOPENXML. Why they don't list this format is beyond me. Perhaps I was looking in the wrong places.