Excel has two date systems, which differ by what date is
equivalent to 1. The standard system uses 0-Jan-1900 while the
other uses 1-Jan-1904. (These dual systems are used for
compatibility with Macintosh software.). Go to the Tools menu,
choose Options, then the General tab. There, ensure that
"1904-date system" is not checked. Do this for all your
workbooks.


--
Cordially,
Chip Pearson
Microsoft MVP - Excel
Pearson Software Consulting, LLC
www.cpearson.com


"dwalesb" wrote in message
...
Why is Excel changing day & date data when I copy & paste?
When I highlight
and copy a range of cells and paste into another sheet, in one
column only
the dates of the material being copied (expressed as 1/23/4567)
change. A
cursory examination seems to indicate a pattern of a one-day
and four-year
change in each cell; e.g. 5/12/2005 becomes 5/13/2009. There
have been some
variations of this where the day apparently stays the same but
the year goes
back 4 years, e.g. 2006 becomes 2002.

During the same operation, although both sheets are in Arial
font, the font
of all the material being copied is changed to Verdana upon
being pasted.