Make Excel 2007 save to .xls by default

[joydeep1]

Excel 2007 uses a highly incompatible .xlsx file format for saving files, making it difficult to share with friends and colleagues who don't have the same version. To change this:

Click the Office button in the top left
Click the Excel Options button
On the left-hand side, select Save
Change the Save files in this format drop down box to Excel 97 - 2003 Workbook
Click OK