I.e., the "Nth <weekday> of <month>" form. This form is much less convenient for timezones where the DST change happens on specific dates, but some applications distribute old versions of Mono that don't bother checking the "wYear" fields of the SYSTEMTIME fields in the TIME_ZONE_INFORMATION structure returned by GetTimeZoneInformation(), and instead always convert the presumed "relative" dates to "absolute" dates. Unsurprisingly, the resulting dates are invalid, and these applications then end up throwing "System.NotSupportedException: Can't get timezone name." when run in such a timezone, typically early during startup. Signed-off-by: Henri Verbeet <hverbeet@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>