When a spreadsheet is generated by opening and saving a .xlt file with the ExcelApplication object, the resulting .xls file should behave like any other .xls file. However, when the user tries to save the ExcelWriter-generated file in Microsoft Excel, Excel defaults to the .xlt extension.

This is a known issue in ExcelWriter which will be addressed in a future version. The workaround is to rename the template file to .xls.