We had an odd thing happen this morning with some Windows XP SP3 workstations. Even though we sync the workstations time with the DC's, they were still off by an hour.
My first assumption was that they didn't have the DST update (before knowing that these were SP3 machines)
Once we saw that they did in fact have SP3 installed I was even more confused as I thought the new DST times were included in SP3. After some digging it looks like you need an update to make sure that the DST works.
You can find the updates HERE.
Once we installed this cumulative update the time was set to normal.
Keep in mind that if you have Outlook and/or Exchange you need to run another update as well. This does not impact Exchange or Outlook 2010.
