I changed my PC time to 1:59 on 3/11 and let it roll to 3:00am. The appointment is still fine (correct time). Why do I need to run the Exchange or Outlook tool?

Q: I changed my PC time to 1:59 on 3/11 and let it roll to 3:00am. The appointment is still fine (correct time). Why do I need to run the Exchange or Outlook tool?
A: Did you apply the Windows Update prior to creating the appointment you have tested with? The update for Windows will cause all newly created appointments to behave properly without the Outlook tool. The tool is just for appointments created earlier.

If the appointment was created after the DST 2007 updates were applied, then that is correct behavior. The issue occurs when you run the Windows OS DST update, your appointments in outlook may be ahead by an hour. A more complete layout of the different scenarios you may face is outlined support.microsoft.com/gp/dst_topissues; more information is also available in support.microsoft.com/kb/931836 and technet.microsoft.com/en-us/library/bb267339.aspx.