We have many files on our network that are maintained by multiple users. We have always gotten a warning message when one person tried to open a spreadsheet that someone else already had open. Since we have been upgrading the PCs to Windows XP and Excel 2002, we are not getting the message. It appears that this happens when the file is created or saved in 2002. It does not happen with files created in Excel 97. I have looked on the microsoft web site but have been unable to find any reference to that problem. Any ideas what could be the problem?