That bug stems from Lotus 1-2-3, and the incompetents in Redmond simply copied it and have still not gotten around to fix it. One of the reasons I consider their company name an accurate description of their brains. Hint: they just need to adjust their weekday function for dates before March 1, 1900 and officially set their zero date to December 30, 1899, as you did. Every existing Excel sheet without dates before March 1, 1900 would be unaffected, and it would open the path for Excel to deal with negative date values. As an aside, it would render the correct number of days if one made the calculation "today - 01/01/1900". Their "reasons" in Excel 2000 incorrectly assumes that the year 1900 is a leap year are of course just "we do not want to think this through, because thinking hurts us too much". Double Hint: OpenOffice and LibreOffice, among others, do not have this problem; they assume day zero to be '30dec1899'd, do not consider 1900 a leap year, and they work with negative date values. PS. To make the joke even funnier: MS Access uses the same internal date values and starts at 12/30/1899, making kb214326 even more ridiculous!
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