As in past versions, the Outlook.hol file that shipped with Outlook 2010 has errors within the 21000+ entries in the file. This time around the major error appears to be for Easter Monday – it’s not on a Monday for several of the years. Oops.
An updated HOL file with the correct date for Easter Monday is at
The updated HOL file works with Outlook 2002, 2003, and 2007 as well as 2010 and includes dates through 2020 (holidays that fall on different dates each year) or 2028 (holidays that always fall on the same date, like Christmas and New Year’s).
If you discover other errors in the holiday file, please let me know.