I have a user where I repaired first his Excel then un-installed and re-installed his office 2007 app and she still gets the error Excel signature Excel.exe AppVer. 12.0.6425A1000, AppStamp 49dC64dd6, Mod. Ver.22.214.171.1243. This happens every time she closes an app in Excel? This is an XP pro OS. Office 2007. I have re-installed and still getting an error.I have run the repair as well. Not sure what the error message means.