One of the workbooks is using a base date of 1900 (normal for WinTel users) and
the other is using 1904 as the base date (normal for Mac users--and users who
want to see negative dates/times).
You could change the base date to match.
In xl2003 menus:
Tools|Options|calculation tab|Check or uncheck the 1904 date system checkbox.
But if you do this, then all the dates in the workbook that you're changing will
be off by 1462 days--and you'll have to make sure you fix all those dates.
But as long as you're aware of the cause, you can add/subtract that 1462 value
to your formula:
=[book2.xls]Sheet1!$A$1 - 1462
(or add that value. It'll depend on what workbook is sending the value and what
workbook is receiving.)
