Suppose you have an Excel XML file and you try to open it in inside an Internet Explorer 32 bit version(by drag drop), it opens just fine in Excel on a Microsoft Office 2010 machine. But if you try to open the same XML file inside a 64 bit version of Internet explorer, you will find the xml text being displayed inside the browser instead of the Excel file being launched.



iexplore.exe attempts to enumerate both Content Type- Text/XML and Content Type-application/vnd-ms-excel, however, in the failing x64 bit iexplore.exe it only enumerates Content Type-Text/XML but Content Type-application/vnd-ms-excel is NOT found in registry.


Resolution :

Adding the following registry entry  resolves the issue and the Excel xml file opens fine even in the 64 bit Internet Explorer–