A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hello,
I too recently have been experiencing issues opening Excel Spreadsheets with Data Validations I created.
After testing I realized it is a compatibility issue between Excel 2003 and Excel 2010. Therefore, if a spreadsheet was created in Microsoft Excel 97-2003 Worksheet (.xls) and you have Excel 2010, when you save your spreadsheet it will not save the validations as it's saving to the Microsoft Excel 97-2003 version. However, if it is saved as, Microsoft Excel Worksheet (.xlsx) or Microsoft Excel 2010 Worksheet (.xlsx) it will. Just remember to delete/remove the older file version.
Good luck,
VLGKJP