GMT Time Zone Transition for Daylight Savings Occurs One Hour Late (320483)


The information in this article applies to:

  • Microsoft Windows NT Server 4.0
  • Microsoft Windows NT Server 4.0 SP1
  • Microsoft Windows NT Server 4.0 SP2
  • Microsoft Windows NT Server 4.0 SP3
  • Microsoft Windows NT Server 4.0 SP4
  • Microsoft Windows NT Server 4.0 SP5
  • Microsoft Windows NT Server 4.0 SP6
  • Microsoft Windows NT Server 4.0 SP6a
This article was previously published under Q320483

SYMPTOMS

The daylight savings time transition for your Windows NT 4.0-based computer that is set to use Greenwich Mean Time (GMT) may occur one hour later than you expect. For example, although the transition should occur at 1:00 AM on the last Sunday in March, it may occur at 2:00 AM. Although the transition back to standard time is scheduled to occur at 2:00 AM on the last Sunday in October, it may occur at 3:00 AM.

CAUSE

This issue may occur if the registry settings for the GMT time zone indicate that the time change should take place one hour later than expected.

RESOLUTION

To modify the default behavior of a time zone in Windows, use either of the following methods.

Manually Modify the Default Behavior

To modify the time zone manually, use one of the following methods:
  • Use the Tzedit.exe utility to adjust the start and end dates for daylight savings time in the time zone.For additional information about how to use Tzedit.exe, click the article number below to view the article in the Microsoft Knowledge Base:

    158195 Time Zone Editor Available on OEM Service Release 2 CD-ROM

  • Create an .inf file to modify the time zone, right-click the file, and then click Install. A sample .inf file entry is listed at the end of this article.

Automatically Modify the Default Behavior

To automate the deployment of the new time zone settings, create an .inf file to modify the time zone, and then use Rundll32.exe to deploy the .inf file. The following command is an example of a Rundll32.exe command you might use, where path\file_name is the location and name of the .inf file:

rundll32 setupapi,InstallHinfSection DefaultInstall 128 path\file_name

Sample .inf File Text for Windows NT

[Version]
Signature = "$Windows NT$"

[DefaultInstall]
AddReg = AddReg

[AddReg]
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified","Display",0x00000002,"(GMT) Greenwich Mean Time (Modified): Dublin, Edinburgh, Lisbon, London"
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified","Dlt",0x00000002,"GMT Daylight Time"
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified","Std",0x00000002,"GMT Standard Time"
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified","MapID",0x00000002,"0,1"
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified","Index",0x00010001,55
HKLM,"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\GMT Standard Time Modified",
"TZI",0x00030001,00,00,00,00,00,00,00,00,c4,ff,ff,ff,00,00,0a,00,00,00,05,
00,02,00,00,00,00,00,00,00,00,00,03,00,00,00,05,00,01,00,00,00,00,00,00,00

Modification Type:MajorLast Reviewed:8/6/2002
Keywords:kbenv kbprb kbui KB320483
©2002 Microsoft Corporation. All rights reserved.