Error opening an Excel file
When opening an Excel file that was exported from IBM Cognos Impromptu you receive an error that says, “The file you are trying to open, “Export.xls”, is in a different format than specified by the file extension. Verify that the file is not corrupted and is from a trusted source before opening the file. Do you want to open the file now?”
If you click Yes the file still opens however the error is annoying. If you open the Excel file in notepad you will also notice it says, “This document is formatted for viewing in Microsoft Excel 2002 and subsequent versions. You are using a previous version of Excel.”
To fix the issue do the following. Back in Cognos click Report>Excel. In the Version drop-down change it from Excel 2002/2003 to Excel 2007 and higher then click OK. Now save the report again as an Excel file. Notice this time the file extension will be XLSX.
Ref – http://www-01.ibm.com/support/docview.wss?uid=swg21350064, https://www-304.ibm.com/support/docview.wss?uid=swg21355007
