I'm in a client office where the version of Office is 2010. At home I only have Office 2003 so I often save spreadsheets in 2003 format (.xls instead of .xlsx) so I can use them at home. When I do this it takes up to 10 seconds to save the file even if there are only a few cells occupied. Previously I've used computers with Office 2007 and found Excel 2007 would save in Excel 2003 format almost instantly.

Is there something wrong in my Office 2010 set up? If so, what I can do to Excel 2010 to make it save faster in the 2003 format?

Could it be that Microsoft has put this slow feature in deliberately to encourage all users of Office 2003 to upgrade, or am I just being paranoid?