has warned that some PCs running Windows XP, 2003 and 2000 are not properly adjusting to last weekend's change in daylight saving time (DST) in the US despite the company's DST2007 patch
Certain computers running the patch continue to display the standard time, rather than the current DST, which went into effect on the morning of 11 March.
The US and Canada recently moved DST forward three weeks in an effort to conserve energy.
But Microsoft has received reports of certain versions of Windows 2000 reverting to the old time settings.
Fixing the issue can require reinstalling the DST patch, editing a system registry
and running the automated script, Microsoft said.
The company is still investigating, and believes that the problem may be related to Windows' security settings.
The Windows clock can be manually adjusted to recognise DST by switching the settings to a new time zone and then reverting to the correct zone.
The adjustment process is relatively simple and not a major concern for home users. For large academic and enterprise networks with hundreds of workstations, however, manually adjusting the time on every PC could take hours.
In order to ease the load on administrators, Microsoft is offering an automated script
that can be run to correctly adjust the time. The script requires that the machine has the DST patch installed.