Since I have upgraded to Office 2007, whenever I try to open a document XLS that I have generated from .NET, I keep receiving this message:
The file you are trying to open, 'Something.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 I answer yes, the file opens ok.
Do I need to update my .NET environment to 2008 and recompile in order to have a XLS file generated by .NET to be ok once opened in Excel?