Excel 2007 Extension Warning On Opening Excel Workbook from a Web Site

raiccs :- i get a warning like this when the excel downloaded from a asp.net developed website

"The file you are trying to open, '[filename]', 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?"  (Yes | No | Help)

any help with this??

pcsmitpra :-- As per MS : The alert prompt is "by design", but the interaction of the cancel action and IE's attempt to open the file again is a known problem under investigation for a future fix.

There is no fix for this alert yet.

But you can configure the Client machine to disable such alerts
Key: HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Security
Value: (DWORD)"ExtensionHardening" = [0 = Disable check; 1 = Enable check and prompt; 2 = Enable check, no prompt deny open]
Default setting if value not present is 1 (enable and prompt)

For more details , Please see http://blogs.msdn.com/b/vsofficedeveloper/archive/2008/03/11/excel-2007-extension-warning.aspx