I'm trying to keep 2 laptops in synch: 1 runs XP Pro SP2 with MS Office 2003; the other runs XP Pro SP2 with MS Office 2007.

I have an Excel spreadsheet that is password protected that I save in .xls (Compatibility Mode). Every time I save it in Excel 2007, I get a message:

"This document is both encrypted and password protected. The Office Open XML Formats available in the 2007 release provide stronger encryption. Do you want to increase the security of this document by converting to an Office Open XML Format?"

Am I correct in assuming that if I did so, I would not be able to open or read the file in Excel 2003?