Incidentally, Windows no longer knows how to correctly convert UTC to U.S. local time for certain dates in March/April or October/November of past years. UTC-based timestamps from those dates are now somewhat nonsensical. It would be very icky for the OS to simply refuse to handle any timestamps prior to the U.S. government's latest set of DST rules, so it simply handles some of them wrong. SQL Server refuses to process dates before 1753 because lots of extra special logic would be required to handle them correctly and it doesn't want to handle them wrong.