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2007 Daylight Savings Time Problem
Contents 1. Intro and General Information 2. Windows 3. Macs
4. Unix 5. PDAs 6. Applications 7. UICalendar

2007 Daylight Savings Time Changes for Microsoft Windows

 

In 2005, the United States congress passed the Energy Policy Act of 2005, which among other things extended the duration of Daylight Savings Time in United States, starting in 2007. Canada and Bermuda have followed suit.

The problem is that, during the extended periods of three weeks in the spring and one week in the fall, many clocks on systems which automatically to change to and from Daylight Savings Time will continue to operate on Standard Time, even though Daylight Time is actually in effect. These uncorrected systems will not be synchronized with other systems which have been fixed.

This page tells you how to correct that, so that the automatic Daylight Time changes take place on the correct date.

We have until March 11, 2007 to fix this problem in the U.S. and Canada.

 
     
 
     
Microsoft on the Daylight Savings Time Problem
   
     
Microsoft Windows Vista
  The production version of Vista already takes into account the 2007 changes to Daylight Savings Time dates. No action is necessary, unless you are in Indiana. Beta versions of Vista should be phased out before March 11, 2007.

Outlook 2007 users are still recommended to run the Outlook Time Zone Update Tool, See Microsoft Outlook below.

State of Indiana only: If you upgraded from any previous version of Windows, such as XP, to Windows Vista, you should check to be sure you are not still operating in the "Indiana" time zone. See Indiana Note below for instructions to correct this.
 
     
Microsoft Windows XP SP2 and Windows Server 2003:
  Microsoft has advised that Outlook users should update Windows and Outlook at the same time. See Microsoft Outlook below.

If you have Automatic Updates configured, you may already have the DST patch. You can confirm this via:

  1. Click Start -> Control Panel -> Add or Remove Programs
  2. Be sure to check the Show Updates box at the top of the window.
  3. Wait 10 seconds then scroll down to the Windows XP- Software Updates bullet.
  4. Do an eyeball search (somewhat tedious) for an entry labeled Update for Windows XP (KB931836)
  5. If you found KB931836 your machine has already been patched. If not, follow one of the steps below to install the patch yourself.

There are four ways to update Windows XP SP2 or Windows Server 2003 for the new Daylight Savings Time change dates:

  1. Windows Update.
  2. Automatic Updates. (Note that the use of Automatic Updates is the only way to obtain this patch without Windows Genuine Advantage Validation.)
  3. Patch manually by following instructions at Microsoft Knowledge Base Article 931836: 2007 time zone update for Microsoft Windows operating systems. XP users should look down the page for the link labeled Download the Update for Windows XP package now.
  4. These versions of Windows can also use the tzedit.exe utility, described below.
State of Indiana only: The above Microsoft updates (Windows Update or the specific patch) do not set Daylight Savings Time if you had selected "Indiana" as your time zone, and cannot take into account the counties that moved from the Eastern time zone to the Central time zone. See Indiana Note below for instructions to correct this.
 
     
Microsoft Windows 95, 98, ME, NT, 2000, XP (no SP), XP SP1
  Microsoft has advised that Outlook users should update Windows and Outlook at the same time. See Microsoft Outlook below.

These no-longer-supported versions of Windows should use the tzedit.exe utility to reset the Daylight Time change dates for your time zone. Here are the instructions, and also links to download tzedit.exe in case you can't find it on your Windows installation CD. Versions of tzedit are available for all levels of Windows, from 95 to XP. Tzedit is compatible with all application software. The alternative timezone.exe utility should not be used, because it is not compatible with some applications such as Lotus Notes.

Using tzedit.exe avoids the need for (risky!) registry modifications described elsewhere. (It makes them for you, correctly, under the covers.)

  1. Download and install the correct version of tzedit for your operating system from one of these sources:
    • Locate tzedit.exe on your Windows installation CD. (Best!)
    • Download tzedit.exe for Windows NT, 2000, XP, 2003 from Microsoft here. When prompted, you should save this on disk somewhere, such as your desktop. Double-click it to run the self-extracting installer program, which by default will install the program into folder C:\Program Files\TZEdit.
    • Download tzedit.exe for Windows 95, 98, ME here. When prompted, you should save this on disk somewhere, such as your desktop. Double-click it to run the self-extracting installer program, which by default will install the program into folder C:\Program Files\TZEdit. This version is intended for Windows 98, but has been found to run fine on Windows 95 and Windows ME as well. (Note: This is a copy of Microsoft's original tzedit.exe for Windows 95, 98, ME which we have downloaded for you because that particular server at Microsoft seems to be swamped much of the time.)
  2. State of Indiana only: You should perform the steps at Indiana Note below, at this point in the process. Then come back here.
  3. Start up the tzedit program by double-clicking tzedit.exe.
  4. In the "Windows Time Zone Editor" window, the time zone you are editing should be highlighted. For instance, for Chicago it should be "(GMT-06:00) Central Time (US & Canada)". (Note that tzedit only edits the settings for a time zone; it does not put any time zone into effect. You do that via Control Panel.)
  5. Click the Edit button.
  6. In the "Edit Time Zone" window:
    • Make sure that Automatically set Daylight Saving Time is checked.
    • Change the Start Day to Second, Sunday, March, 02:00:00
    • Change the Last Day to First, Sunday, November, 02:00:00
    • Don't change anything else. Click OK and Close to finish.
    If this computer is moved between time zones, such as a laptop that is carried between Chicago and New York, repeat the above changes within the tzedit program for each time zone your computer might visit.
  7. Do not skip these remaining steps, or your new changes will not take effect.
    Click Start --> Settings --> Control Panel --> Date/Time --> Time Zone (tab)
  8. Select some other time zone besides yours, i.e. any time zone other than (GMT-06:00) Central Time (US & Canada). Click Apply.
  9. Now select your time zone again, i.e. (GMT-06:00) Central Time (US & Canada). Click OK.
Links:
 
     
Microsoft Windows Active Directory
 

It is critical that all client machines participating in Active Directory update their operating systems as described in this section. Otherwise, if UTC is off by an hour, there will be Kerberos authentication failures. Kerberos does not tolerate clock settings that differ by more than 5 minutes. Anyone who simply changes their system clock manually, without also applying patches and/or changing their time zone, will have a UTC time setting that is off by an hour, and will fail to authenticate with Active Directory.

 
     
Microsoft Outlook
 

You need to make sure that the underlying operating system is updated for the change, and then you need to update Outlook itself. Calendar events created during the extended periods of Daylight Time may appear at the wrong times. Microsoft has provided a tool to fix these problems.

Important Notes:

  • !!!Oracle has not certified the Microsoft Outlook Time Zone Update Tool for Oracle Connector for Outlook and strongly recommends you do not run the Outlook Timezone Update Tool if you are using Oracle Connector for Outlook to connect to UICalendar. Instead, fix the entries by hand as described in UICalendar Problem with 2007 Daylight Saving Time Change.

  • If you use Outlook to access a Microsoft Exchange Server, we recommend you contact your Exchange administrators before running the tool.

  • However, Microsoft advises that users "should minimize the time lag between applying updates to operating systems and running the Time Zone Data Update Tool." This means that you should wait before updating Windows, until you have the Outlook Time Zone Update Tool downloaded, installed, and ready to run.
Microsoft Office Outlook: Prepare calendar items for Daylight Saving Time changes in 2007
Excellent article, readable by anyone, that describes the problems and the solutions very clearly. Recommended reading for all Outlook users.
Microsoft Outlook Time Zone Update Tool
 
Addressing daylight saving time using the Outlook Time Zone Data Update Tool
Excellent, detailed technical documentation of all aspects of the Daylight Time problem vis-a-vis Outlook. Technical information for the technically inclined. Others should read the more general article in the first link above.
Preparing other Microsoft software products for the 2007 DST changes
 
 
     
Microsoft Exchange Server
  Microsoft Exchange Server needs updates in order to function properly after March 11, 2007. These updates are described here: Microsoft Windows: Preparing for daylight saving time changes in 2007

Exchange system managers will also need to run the Outlook Time Zone Data Update Tool, described above with Outlook.

 
     
Indiana Note:
 

Microsoft Windows (all versions) contains a "(GMT-05:00) Indiana (East)" time zone, which was defined to remain on Eastern Standard Time all year. However, all of Indiana now goes on Daylight Savings Time in the summer. Furthermore, some Indiana counties moved from the Eastern time zone to the Central time zone.

  1. Click here for a link to the new official new time zone map of Indiana. (PDF) to determine if your Indiana county is now in the Eastern or Central time zone. Pay careful attention to this map because some counties moved from the Eastern to the Central time zone.
  2. Click Start --> Settings --> Control Panel --> Date/Time --> Time Zone (tab)
  3. Change your time zone to either (GMT-05:00) Eastern Time (US & Canada) or (GMT-06:00) Central Time (US & Canada), depending on your location on the Indiana map above.
  4. Make sure that Automatically adjust clock for daylight saving changes is checked, because now all of Indiana observes Daylight Savings Time.
  5. Click OK.
 
     
See Also
 

The notes under 3. General Considerations on the introduction page. Various information there applies to Windows. (And to Indiana.)

 
DST Problem Previous:  1. Intro and General Information Next:  3. Macs


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