3848 Campus Drive, Suite 117
Newport Beach, CA  92660
(949) 724-1230  Fax (949) 724-1288

The Daylight Saving Time (DST) Problem and Some Solutions

Note - Now that it's past March 11th...
If you apply any of the operating systems patchs below at this point, then you need to make Windows transition into the Daylight Saving Time period (note not all other apps need this, just Windows itself). So after applying your operating system patch, back the date and time up to March 11th at about 1:59:50 AM. Hit OK to apply the time. You will soon see the time change to 3:00 AM. Then just set the date and time to what is correct.


The purpose of this page is to provide some self-help tools for "workstation" users.

Please see our DST Notes file
for an overall introduction. Essentially there are patches for the operating system (OS); for larger companies this area includes Exchange Server. Next, programs with calendars will need some appointments adjusted. This particularly includes Outlook, but also Act, Notes and other such programs. Handheld devices like Palm, Blackberry, and Windows CE based ones also have some patches available.

At this point I want to emphasize, the main problem for people will be with Outlook, and put some precautions right here for Outlook users:

Outlook Precautions

  • Print out your Calendar now, from 3/05 to 5/05 in a week view, before patching.
  • Treat all your appointments in the 3 weeks to 4/01 as suspect (this per Microsoft).
  • Put time entries (like "Dr. Appointment - 10 am") in the title or body of any calendar entries.

Operating System Help

Windows 2000
Microsoft has no patches for you. So the easiest thing is to use IntelliAdmin's free tool to patch your time zones: IntelliAdmin patch Here.

There is also a Microsoft utility for manually editing time zones: TZEdit.
TZedit's help file if need is here: tzedit help file.

Windows XP SP2
Microsoft only has a patch for people who are fairly up to date. In fact, if your automatic updates has been turned on, your pc may well have gotten this update. It will not hurt to run it twice. XP SP2 patch

Windows XP SP1 and SP Nothing
You could update to SP2 and then put on the above patch. Or you could just use the IntellAdmin patch above. But note, for the Outlook tool TZMove (below), you will need SP2 for it to run.

Windows 98/ME and 95
IntelliAdmin has a patch for Windows 98/ME, but Windows 95 may out of luck for a patch; however changing the time manually would certainly work. We recommend making the reference to GMT be correct (West Coast uses GMT-7:00) in DST.


As a reminder, you should have printed out your Calendar and maybe even backed it up. Then after the OS is patched, you can consider some fixups for the appointment in the 3 week window before 4/01 (note also for the 1 week period after 10/28).

Consider what is happening "under the hood" of the appointments in Outlook. Some peculiarities can certainly happen, even for what a typical XP user might face: If in January you entered some appointments in the new 2007 DST period, say for example on March 15th, then those entries will be wrong next week during when we change to the new DST time period. Then say in late February, your Windows automatic update downloaded and installed the fixes to your time zone settings; so then if on March 1 you created some entries for March 16th, those entries will be right.

Note: the unupdated error for single entries in the March timeframe is that they will appear an hour later than actual.

Running this tool tries to identify which entries need fixing. We aren't sure if its rules work as well as one would hope, so some manual fixups are still necessary. Additionally, the tool does not seem to handle tentative appointments (at all) or recurrent appointments very well. For tentative appointments, you will have to manually fix them, and for recurrent ones you would recreate the series.

And please note, we HAVE seen many calendars get cleaned up 100% fine with this tool; it's just there are some exceptions for some users.

The fixup tool: From Microsoft's KB article 931667: TZmove
By the way, this tool (thanks Microsoft) only works on systems with Windows 2000 SP4 or Windows XP SP2.

Other Applications

To install the update using your Treo, open the web browser on the device and install the daylight saving time update found at:


Tip: To type the underscore character on your Treo, press the option key, then s, then Alt. If you prefer, you can install the update using your PC (Hotsync via USB connection), download the update and sync to your Treo. More information is available at Palm's website.

For users of Act 2005 and up, there is a utilty to run to fix up calendar entries. Please refer to the main Act website.

For PC workstations, we are mainly recommending a wait and see approach on this (and basically we are not expecting problems). For Unix boxes and other production/website situations reliant on Java, there ARE updates to several modules.

Microsoft Resources
There are many, but to start, here is the main page to get started

On the right of that page is their TOP ISSUES link

Technet article on some Exchange Server issues

Notice from the 'top issues' link the steps Microsoft took for their own deployment:

Please note that in a networked environment there are some significant risks. One example is to update the Windows 2000/2003 server but to leave off updating an older workstation but then "manually" updating the date on the workstation. This can lead to an inability to login due to the way Kerberos handles date/time in the authentication process with the server.

Manual Date/Time Setting
(For "Home" Users and Simple Networks)
Going without patches...if one "just" changes the time, you can get some Outlook calendar entries right in the March period but still be wrong in April-Oct, or vice versa. Our primary recommendation is to turn off Automatic DST setting, then picking a timezone with the proper GMT setting. For the West Coast, in the DST period, this will be GMT-7:00 (and later changing back to DST-8:00 in the fall). This will make Outlook time errors show up in March appointments, but the rest of the April onwards DST period will be okay. Alternatively, keeping the timezone setting at GMT-8:00 will make the Outlook entries be correct in the March timeframe but be wrong in the rest of the DST period.

So if you want the least trouble with Outlook entries, use GMT-8:00 for the 3 weeks in March and and manually change the timezone to GMT-7:00 in the rest of the DST. But please note that using GMT-8:00 in the 3 weeks of March is actually incorrect and could negatively affect some other application(s) you have which do not have problems like Outlook's.

And don't forget there is a week at the end of the DST period where you would have to run the reverse of your strategy.