How to Recover Data From a Corrupt Excel Workbook

When trying to recover data in a Excel workbook that appears to have some data corruption, the best method recommended is to "round trip" the file.

If the file was originally created in Excel 2003,
  1. Make a backup copy of the file
  2. Open the file in Excel 2003 
  3. Save As - select type Web Page (.html), save and close the file
  4. Open the .html file in Excel 
  5. Save the file as a .xls
This technique is also recommended for Excel 2007 and 2010