How to suppress the file corrupt warning at Excel download?

Question

I have a web page which links to an Excel 2007 worksheet. It is a .xls file and not .xlsx file. When I click on the link I get the usual dialog box

Answer 1

This problem results from a feature called Extension Hardening, and you can find more information about it here

I've run into this problem a lot in my projects, and like Jon said, turning off Extension Hardening is something that will have to be done by each client side user.

Unfortunately, the link above also states that there are no expected changes to this code until at least Office 14.

Answer 2

If you're using the handy cfcontent trick to output as an excel file, consider using cfx_query2excel, it will write real excel files that should get you past this. It's a Java library and was worth it.

Best of luck.