Microsoft Daylight Saving Time & Time Zone Blog

This is the blog maintained by staff at Microsoft to provide general information, announcements and provide answers to Frequently Asked Questions (FAQs) related to daylight saving time (DST) and time zone (TZ) changes around the world. * Important Notice

Argentina is changing their daylight saving time on December 30

Argentina is changing their daylight saving time on December 30

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(cross posted from this blog entry)

This past week, the government of Argentina approved a new change to their observance of daylight saving time in the country effective this Sunday, December 30, 2007 at 12:00am to March 16th, 12:00 for Argentina.

According to Reuters, "under the new law, which both houses of Congress passed the same day, the time in Argentina will jump forward an hour starting on Sunday. The clocks will turn back on March 16."  Information is also available via our Argentinean web site at http://www.microsoft.com/argentina/dst.

Currently Argentina is using GMT-3, with this change we will be using GMT-2.  This fast-tracked change came with little advance notice and little reason for a fast implementation.  Many of our customers are in a so-called "freeze period" where they do not make any changes or deploy any updates to their networks or systems. 

Possible changes:  Some customers may select to manually move their own users and systems to an appropriate time zone (such as the Mid-Atlantic TZ) on December 30 and move clocks back to Buenos Aires (GMT -3) on March 16.   Other customers may wish to follow the guidance below for manually changing the registry.  (See the section below for considerations of these changes.) 

In addition to Microsoft products, other software, OS releases and hardware (phones, routers, switches and managed devices) may require updates/ changes. 

Upcoming Daylight Saving Time implementation for Argentina in 2007-2008

The steps provided in this bulletin were created to mitigate the impacts that the daylight saving time implementation will cause for customers in Argentina. These are the impacts primarily anticipated at the time this document was written, and the effects that customers may face are not restricted to them.

The suggested actions on this bulletin might receive additional testing. Therefore, if you are not severely affected by the DST changes in Argentina, we recommend that you wait for the next DST cumulative update that will likely contain the updates for Argentina.

This bulletin contains information about how to modify the registry. Make sure that you back up the registry before you modify it.  Make sure that you know how to restore the registry if a problem occurs.

The information described in this document may change without notice. In addition, customers should be aware that further guidance will be provided at any time by Microsoft.

Background – implementation of Daylight Saving Time for Argentina in 2007-2008

The government of Argentina has announced the implementation of daylight saving time (DST) in Argentina. The following are the start and end dates for the daylight saving time defined:

  • Daylight saving time begins:  Sunday, December 30th, 2007 at 00:00 A.M local standard time.
  • Daylight saving time ends:  Sunday, March 16th, 2008 at 00:00 A.M local daylight saving time.

Currently, computers in Argentina use the “(GMT-03:00) Buenos Aires, Georgetown” time zone setting. However, the default values for the “(GMT-03:00) Buenos Aires, Georgetown” time zone setting in Microsoft Windows do not reflect the daylight saving time start and end dates defined by the government.

This bulletin summarizes the actions recommended for customers in Argentina to address the implementation of daylight saving time and mitigate its impacts.

General recommendations for customers in Argentina

1. In order to update Windows PC operating systems, we recommend administrators to create a new time zone to reflect the DST implementation in Argentina. Please read the section “How to update Windows Servers and Desktop Operating Systems” for details on the recommended steps.

2. Please note that if you adjust the machine’s clock manually, you may have adverse effects on your environment.

3. Before you apply the changes on Windows Operating Systems to reflect the DST dates in Argentina, be aware of potential issues that will affect Microsoft Office Outlook and Exchange Server. Read “Impacts for Outlook and OWA Clients” sections for more details.

4. Contact Microsoft Support prior to any modification if you are unsure about the steps to follow in order to be prepared for the DST implementation in Argentina.

How to update Windows Servers and Desktop Operating Systems

This session is based on the following article:

914387 - How to configure daylight saving time for Microsoft Windows operating systems

http://support.microsoft.com/default.aspx?scid=kb;EN-US;914387

IMPORTANT INFORMATION:

  • There is no hotfix available at this time to update Windows Operating Systems with the DST dates for Argentina.
  • The current version of KB 914387 does not contain information about the new DST settings for Argentina.
  • The recommendation at this time is to create a new time zone to reflect the DST dates defined by the Argentina government. To do so, please proceed as follows:

Updating Windows Servers and Desktop Operating Systems

1. Create a registry file that will contain a new time zone for Argentina, following these steps:

1.1. Click Start, click Run, type notepad, and then click OK.

1.2. Copy the following registry information, and then paste it into the Notepad document:

Windows Registry Editor Version 5.00

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Argentina Standard Time]

"Display"="(GMT-03:00) Buenos Aires" 

"Dlt"="Argentina Daylight Time"

"Std"="Argentina Standard Time"

"TZI"=hex:b4,00,00,00,00,00,00,00,c4,ff,ff,ff,00,00,03,00,00,00,03,00,00,00,00,\

  00,00,00,00,00,00,00,0c,00,00,00,05,00,00,00,00,00,00,00,00,00

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Argentina Standard Time\Dynamic DST]

"FirstEntry"=dword:000007d6                 

"LastEntry"=dword:000007d8

"2008"=hex:b4,00,00,00,00,00,00,00,c4,ff,ff,ff,00,00,03,00,00,00,03,00,00,00,00,\

  00,00,00,00,00,00,00,0c,00,00,00,05,00,00,00,00,00,00,00,00,00

"2007"=hex:b4,00,00,00,00,00,00,00,c4,ff,ff,ff,00,00,01,00,01,00,01,00,00,00,00,\

  00,00,00,00,00,00,00,0c,00,00,00,05,00,00,00,00,00,00,00,00,00

"2006"=hex:b4,00,00,00,00,00,00,00,c4,ff,ff,ff,00,00,00,00,00,00,00,00,00,00,00,\

  00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00,00

 

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\SA Eastern Standard Time]

"Display"="(GMT-03:00) Georgetown"

1.3. On the File menu, click Save As.

1.4. Select a destination, and then type TZupdate.reg in the File name box. 

1.5. In the Save as type box, click All Files, and then click Save.

2. Import this registry key on target machines by double clicking in the TZupdate.reg and clicking ‘Yes’ when prompted. All machines (clients and servers) must be updated with this registry information.

2.1. After importing the registry key, the time zone “(GMT-03:00) Buenos Aires, Georgetown” will be renamed to “(GMT-03:00) Georgetown”.

image
“(GMT -03:00) Buenos Aires, Georgetown” becomes “(GMT -03:00) Georgetown”

2.2. A new time zone named “(GMT -03:00) Buenos Aires” will be created.

image
New time zone “(GMT -03:00) Buenos Aires” – it contains the DST dates for Argentina

2.3. Users located in Argentina will need to change the time zone from “(GMT -03:00) Georgetown” to the new “(GMT-03:00) Buenos Aires” time zone.

2.4. Note that on the new time zone “(GMT -03:00) Buenos Aires” the option “Automatically adjust clock for daylight saving changes” is selected by default. Users should not uncheck this option.

3. In order to deploy these time zone changes in a corporate environment, you can use a startup script as described in the session “Deploy the registry file with the new DST information using Group Policy” below.

Deploying the registry file with the new DST information using Group Policy

1. Click Start, click Run, type notepad, and then press ENTER. 

2. Copy the following code, and then paste it into the Notepad document.

@echo off

regedit /s \\contoso.com\NETLOGON\TZupdate.reg

Note: You must replace the \\contoso.com notation above with the actual DNS domain name for your Active Directory domain.

3. On the File menu, click Save As.

4. DST2007Update.cmd in the File name box. 

5. In the Save as type box, click All Files, and then click Save. 

6. Copy the following files to the Netlogon share folder of the domain controller that holds the PDC emulator role in the domain:
- TZupdate.reg 
- DST2007Update.cmd 

7. Wait until Active Directory replication occurs. Also, wait until the files and folders in the system volume (SYSVOL) shared folder replicate to domain controllers in the domain. 

8. Click Start, click Run, type control admintools, and then click OK. 

9. Double-click Active Directory Users and Computers

10. Select an Organizational Unit (OU) which contains the computers that you want to apply this script to. In this example, we will use an OU that is named DST2007-W2K. This example also assumes that this OU contains computer accounts.

11. Right-click the DST2007-W2K OU and then click Properties. 

12. Click the Group Policy tab, click New, type DST Registry Update, and then press ENTER. 

13. Click Edit. The Group Policy Object Editor tool starts.

14. Expand Computer Configuration, expand Windows Settings, and then click Scripts (Startup/Shutdown). 

15. Double-click Startup, and then click Add. 

16. In the Script Name box, type the universal naming convention (UNC) path of the DST2007Update.cmd file that is located in the Netlogon share. For example, type \\contoso.com\NETLOGON\DST2007Update.cmd

17. Click OK two times. 

Note: Client computers that are within the DST2007-W2K organizational unit will run the startup script the next time the machine starts up. This will make the system to recognize the existence of the new “(GMT -03:00) Buenos Aires” time zone, however you still need to move to the new time zone that was just created. Please read the section ‘Changing the computer time zone via startup script’ for information on how to automatically change the time zone using a group policy.

Changing the computer time zone via startup script

1. Click Start, click Run, type notepad, and then press ENTER. 

2. Copy the following lines, and then paste it into the Notepad document.

@echo off

ver |find /i "6.0">nul

IF %errorlevel% EQU 0 GOTO end

 

control.exe timedate.cpl,,/Z Argentina Standard Time

:end

3. On the File menu, click Save As.

4. Select a destination, and then type ChangeTZ.cmd in the File name box. 

5. In the Save as type box, click All Files, and then click Save. 

6. Copy the file to the Netlogon share folder of the domain controller that holds the PDC emulator role in the domain.

7. Wait until Active Directory replication occurs. Also, wait until the files and folders in the system volume (SYSVOL) shared folder replicate to domain controllers in the domain. 

8. Click Start, click Run, type control admintools, and then click OK. 

9. Double-click Active Directory Users and Computers

10. Select an OU that contains the computers that you want to apply this script to. In this example, we will use an OU that is named DST2007-W2K. This example also assumes that this OU contains all computer accounts. 

11. Right-click the DST2007-W2K, and then click Properties.

12. Click the Group Policy tab, click New, type DST Time Zone Change, and then press ENTER. 

13. Click Edit. The Group Policy Object Editor tool starts.

14. Expand Computer Configuration, expand Windows Settings, and then click Scripts (Startup/Shutdown). 

15. Double-click Startup, and then click Add. 

16. In the Script Name box, type the universal naming convention (UNC) path of the ChangeTZ.cmd file that is located in the Netlogon share. For example, type \\contoso.com\NETLOGON\ChangeTZ.cmd

17. Click OK two times. 

Important information about procedures described in this document:

a. You can import the registry key detailed above in any Windows Operating system language. However since it contains display information, the new time zone display names will be based on the “English US”  language, as follows:

  • Argentina Daylight Time
  • Argentina Standard Time

b. The information on “Deploying the registry file with the new DST information using Group Policy” session can be applied to all computers in the network.

c. The information on “Changing the computer time zone via startup script” should be applied only to computers located in Argentina.

d. The instructions above can be applied on Windows 2000, Windows XP and Windows Server 2003 Operating systems, however after performing these instructions on a Windows 2003 operating system, the current time zone may not be automatically changed to the ‘(GMT -03:00) Buenos Aires’. Users may need to change the time zone manually after importing the registry key via startup script on Windows 2003 machines.

e. The instructions above are not supported on Windows Vista operating systems.

Impacts for Windows Mobile users in Argentina

Windows Mobile devices will show all items (messages and appointments) 1 hour off during the DST period (December 30, 2007 to March 15, 2008).

These devices require an update that is not available at this time. Information will be released as soon as it becomes available.

Impact for Outlook clients in Argentina

Three factors affect the scheduling of a meeting and appointment in Outlook:

  • The computer's clock setting (time).
  • The computer's local time zone setting.
  • The computer's daylight saving time adjustment setting.

Outlook time stamps the message request with the Greenwich Mean Time for the meeting. Outlook calculates Greenwich Mean Time by using the computer's clock time, plus or minus the local time zone adjustment, minus (depending upon the time of year) the daylight-saving time adjustment. If any of the three factors listed above are incorrect at the time the item is saved or if there is a modification afterwards (such as a DST change), the meeting time will be incorrect.

In the Argentina scenario, after moving Windows clients and servers to the new time zone “(GMT-03:00) Buenos Aires”, Outlook calendars will display items 1 hour ahead their actual time during the DST period (December 30, 2007 to March 15, 2008). 

In addition, because there was a time zone move, all appointments need to be updated to reflect the new time zone information.

As such, "rebasing" of the items will be required to allow them to display the proper time and the proper time zone information.

The Time Zone Data Update Tool for Microsoft Outlook can be used to update your calendar items to the new time zone “(GMT-03:00) Buenos Aires”.

1. What can I do to fix my appointments?

-or-

  • Manually modify each appointment after the operating system time zone has been changed.

The Time Zone Data Update Tool for Outlook must be used with the /PHYSICALMOVE command-line parameter, which is not the default mode for the tool and, perhaps most importantly, not the mode in which the tool is launched automatically during setup.

Many of the special command-line options available for the Outlook tool are not supported when doing a time zone move.  Most notably, /QUIET mode is not supported and the procedure needs manual intervention from the end-user.

Step by step procedure to use “Time Zone Data Update Tool for Microsoft Outlook”

The following describes the ideal set of steps to be followed by end-users performing a time zone move:

I. Update the Operating System’s time zone information according to the section “How to update Windows Servers and Desktop Operating Systems” above

II. Switch the current time zone “(GMT -03:00) Georgetown” to the target time zone “(GMT -03:00) Buenos Aires”.

III. Download and run the installation package from http://www.microsoft.com/downloads/details.aspx?familyid=%20E343A233-B9C8-4652-9DD8-AE0F1AF62568&displaylang=en.

IV. When the tool is automatically launched as part of the above install, click the Cancel button.

image

NOTE: Step IV is necessary because the tool is automatically launched in time zone update mode rather than physical move mode. The above screen shot shows the tool in time zone update mode; note that there is only one time zone selector for “Your Time Zone” in update mode. Below you can find a screen shot of the tool running in time zone move mode; note that there are two time zone selectors for “Original Time Zone” and “New Time Zone.”

V. Restart the installed executable using the /PHYSICALMOVE switch:

a. On a 32-bit OS, run “%PROGRAMFILES%\Microsoft Office\Office12\Office Outlook Time Zone Data Update Tool\tzmove.exe” /PHYSICALMOVE

b. On a 64-bit OS, run “%PROGRAMFILES(x86)%\Microsoft Office\Office12\Office Outlook Time Zone Data Update Tool\tzmove.exe”  /PHYSICALMOVE

NOTE: Do not confuse the installation package with the tool itself (both have the same name tzmove.exe). The resulting dialog should look like the following:

image

VI. Properly select “(GMT -03:00) Georgetown” from the “Original Time Zone:” drop down, and “(GMT -03:00) Buenos Aires” from the “New Time Zone:” drop down and click OK.

NOTE: As with standard time zone updates, the tool defaults to updating affected items on your Calendar and in your Reminders folder.  If you would like to update additional items (e.g. items in additional Calendars or a PST), you can do so by clicking the ‘Custom…’ button and manually selecting the target folder.

VII. The tool will inspect your mailbox and will report how many appointments will be moved:

image

If you click “Details” the appointment list will appear and you will be able to select all (default) or some of the appointments. In a normal situation you will move all the appointments to the new time zone. Click “OK” in the following dialog to proceed moving the appointments. A log file “Outlook Time Zone Update .log” will be generated in the %temp% directory.

image

VIII. After moving Click “OK” again to close the tool.

In addition to simply using the above guidance, IT administrators might consider streamlining the above procedure as follows:

  • Automatically launch the tool in time zone move mode after having installed it in quiet mode.
  • The above two steps can be captured in a simple .bat file similar to the following thus allowing end users to combine steps III, IV, and V above into one (i.e. just launch the .bat file):

@echo off

<path to tzmove.exe that was saved from http://www.microsoft.com/downloads/details.aspx?familyid=%20E343A233-B9C8-4652-9DD8-AE0F1AF62568&displaylang=en>\tzmove.exe /quiet

"%PROGRAMFILES%\Microsoft Office\Office12\Office Outlook Time Zone Data Update Tool\tzmove.exe" /physicalMove

@echo on

This is the maximum level of automation allowed by the tool in Time Zone Move mode. As you can see it still requires end-user intervention from the dialog in step V and forward.

2. What is the best time to update my calendar?

The best time to update your calendar items is as soon as you have changed your time zone settings in your operating system and before any new calendar item is created, accepted or sent.

3. Can I use the “Exchange Calendar Update Tool” to update (rebase) the appointments/meetings on the Exchange Server?

You cannot use “Exchange Calendar Update Tool” in the Argentina scenario. The Exchange Calendar Update Tool is not designed to update appointments when there is a move from one time zone to another.

The update has to be done on each client either manually or using the “Time Zone Data Update Tool for Microsoft Outlook”.

Impact for Outlook Web Access clients in Argentina

  • The new time zone “(GMT -03:00) Buenos Aires” created following the recommendations on section “Updating Windows Servers and Desktop Operating Systems” will not be available on the OWA (Exchange Server 2000 and Exchange Server 2003) time zone options at this time. In order to have this new time zone available in OWA, there is a dependency on an index key which is not currently defined. We expect this to be defined over the next months.
  • After you configure Windows clients and servers to use the new time zone “(GMT -03:00) Buenos Aires”, OWA users using “(GMT -03:00)  Buenos Aires, Georgetown” on the OWA time zone options, will receive the following warning when accessing their inbox:

image

  • When you open a message in OWA, it will be displayed with the incorrect time during the DST period. This is related to the CDO components in Exchange and there is no workaround for this behavior at this time.

Additional known issues for Exchange Server and Outlook clients

  • Meeting invitations sent by Outlook clients between different Exchange organizations may be off by 1 hour. This is related to the CDO components in Exchange and there is no workaround for this behavior at this time.
  • After Exchange Server 2007 is updated with the new time zone “(GMT -03:00) Buenos Aires”, the “Microsoft Exchange Mail Submission” and “Microsoft Exchange Transport” services should be restarted.

Additional recommendations

  • Simulate the changes on a lab environment, so you know what will happen and what to expect.
  • Before doing any change in Outlook, request the users to print their schedule so they have a reference to follow if they have to manually update the appointments or double check after running the Time Zone Data Update Tool for Microsoft Outlook.

— For the meetings with multiple attendees only the meeting requestor should update the time. An update will be sent automatically by the Time Zone Data Update Tool for Microsoft Outlook.

Frequently Asked Questions

1. Can I use Tzedit.exe to modify the time “(GMT -03:00) Buenos Aires, Georgetown” in order to include the DST dates defined for Argentina?

Based on previous experiences with other time zone updates released by Microsoft, this will not be the definite solution. The time “(GMT -03:00) Buenos Aires, Georgetown” is shared with other country (Guyana) and this country is not adopting DST at this time.

We preferred the option to have a new time zone as this goes in line with what was done in the past for countries like Venezuela. In addition, we avoid impacts for countries currently using “(GMT -03:00) Buenos Aires, Georgetown” other than Argentina.

2. Do I have to update machines outside Argentina?

It is recommended that you apply the registry updates to all machines, including the ones outside Argentina. However, the time zone move should be performed only on machines located in Argentina.

3. Should I manually adjust the machine’s clock on December 30th 2007?

You should not adjust the machine’s clock manually. This can cause adverse effects on your environment.

4. What calendar items will be updated using the Time Zone Update Calendar tool for MS Outlook?

Only appointments created using the original time zone “(GMT -03:00) Buenos Aires, Georgetown” which occur after the date/time the tool is executed.

5. Should I move to the time zone “(GMT -02:00) Mid-Atlantic” on December 30, 2007 and move back to “(GMT -03:00) Buenos Aires, Georgetown” after March 16, 2008?

This is a feasible workaround for home users; however it may not be the best option for corporations/enterprise customers as it can cause undesirable results on Outlook calendars.

One of the side effects from this workaround is related with appointments created in different time zones. For instance, appointments created before the change will be in “(GMT-03:00) Buenos Aires, Georgetown” and appointments created during the DST will be on “(GMT -02:00) Mid Atlantic”.

Another effect is that appointments created after March 16th 2008 during the DST time will be off by one hour when the user go back to “(GMT-03:00) Buenos Aires, Georgetown”.

If the Time Zone Data Update Tool for Microsoft Outlook needed to be run for some reason, users would need to run it twice, once for the items created in “(GMT-03:00) Buenos Aires, Georgetown” and once for “(GMT -02:00) Mid Atlantic”.

There may be more side effects on this workaround; this option was not thoroughly tested.

6. Is there any public guidance/documentation available on this matter?

Please direct your customers to:

§ LATAM Team Blog – http://blogs.technet.com/latam/default.aspx

§ Exchange Team Blog - http://msexchangeteam.com/archive/2007/12/28/447791.aspx

§ Microsoft Argentina web site - http://www.microsoft.com/argentina/dst/


If you want more information, you can refer to the following Microsoft articles:

195900 - How Outlook handles time zones for meeting requests

http://support.microsoft.com/?id=195900

931667 - How to address time zone changes by using the Time Zone Data Update Tool for Microsoft Office Outlook

http://support.microsoft.com/default.aspx?scid=kb;EN-US;931667

914387 - How to configure daylight saving time for Microsoft Windows operating systems

http://support.microsoft.com/default.aspx?scid=kb;EN-US;914387

325413 - INFO: Task Scheduler Behavior at Daylight Saving Time Transitions and Other Events

http://support.microsoft.com/default.aspx?scid=kb;EN-US;325413