In some Microsoft Office/Windows versions, you can no longer open the export file directly from your browser.
In order to view the exported file, the user needs to save the file first, and open it from MS Excel. 

The problem may occur in the following Office/Windows versions:

• Office 365/windows 10
• Office 2013 and upgrading to windows 7,8,10
• any office upgrade.

See Microsoft Community and  Microsoft Office Support websites for solutions.