With the upcoming Daylight Saving Time change and the associated patch that will configure Windows to make the change on the morning of March 11th, we have had quite a few calls regarding the DST patches and how to test Windows to ensure the patch is working.  The method used to test DST has not changed with the installation of the patch, but there is some confusion about how best to verify that the correct changes are being applied.

One of the first things to consider is that there is a recommended order of patching.  The Microsoft site on Preparing for Daylight Saving Time changes in 2007 covers several scenarios.  The General sequence of update actions & special considerations can be found here.

OK - so now that you know the proper patch order - how can you run some simple tests to make sure that you get to actually sleep on March 11th?  From the basic Windows perspective, the steps below should be sufficient to verify basic functionality.  Remember that for Exchange & Outlook, there are special considerations - please make sure that you have read the information on the Microsoft site before testing the change(s).

How To test DST on Windows after applying the patch:

Windows will not automatically adjust the time if you advance the clock to a date/time that is beyond the daylight saving time date. Another words the clock will not automatically move an hour ahead or behind by simply changing to a date that is beyond the configured DST date (ex. Changing the clock to May 5, 2007 will not result in an hour jump on the clock, the clock will remain the same)

IMPORTANT: DO NOT test this on a live production system.  More specifically, do not test on a Domain controller or other time sensitive systems. There are numerous issues that can occur, especially in an Active Directory environment if there is a time skew between servers.

  1. Unplug the test system from the network (this will prevent the Time service from automatically synchronizing its time with a Time Server)
  2. Open the Date and Time properties
  3. Set the clock to 1:58:00 AM and click on 'Apply' (do not set the date yet)
  4. Set the Date to Mar 11, 2007 and click on 'Apply'
  5. Close the Date and Time Properties dialog box
  6. Watch the clock at the lower right corner.

Expected results:
At 2:00 AM on Mar 11 the system clock will change as follows. 
From: 1:59 AM
To: 2:59 AM
Then: 3:00 AM

Once you have completed your test, ensure that you reset the system date & time to the proper values before restoring Network Connectivity.

Additional Resources:

 - Aurthur Anderson