Australian Time Zones End Daylight Savings Time on Wrong Date

• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51. and 4.0

SYMPTOMS

Windows NT ends daylight savings time in the Brisbane, Melbourne, Sydney and Adeliade time zones on the first Sunday in March. The time zones do not actually officially switch back to standard time until the last Sunday of March.

CAUSE

The date that Windows NT ends daylight savings time is set incorrectly in the system registry.

WORKAROUND

To work around this problem, do one of the following:

• The Windows NT 4.0 Resource Kit includes a TZEDIT program. Use this program to change the affected time zones to end daylight savings time on the last Sunday in March.
• If the Resource Kit is unavailable, make the following changes in the system registry.

  WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

  For information about how to edit the registry, view the "Changing Keys And Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Not that you should back up the registry before you edit it.

  1. Start Registry Editor (Regedt32.exe).

  2. In the HKEY_LOCAL_MACHINE subtree, find the subkey for the Adelaide

        time zone:
  

           SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Cen.
           Australia Standard Time
  
           NOTE: The above registry key is one path; it has been wrapped for
           readability.
  
     3. Open the value TZI in your time zone key to get into the binary
        editor.
  
     4. You should see binary information like this:
  
        C6FDFFFF00000000C4FFFFFF0000030000000100020000000000000000000
        A00000005000200000000000000
  
        NOTE: The above binary information is one line; it has been wrapped
        for readability.
  
     5. Change this value to the following value:
  
        C6FDFFFF00000000C4FFFFFF0000030000000500020000000000000000000
        A00000005000200000000000000
  
        NOTE: The above binary information is one line; it has been wrapped
        for readability.
  
     6. In the HKEY_LOCAL_MACHINE subtree find the subkey for the Brisbane,
        Melbourne, Sydney time zone:
  
        SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones\Sydney
        Standard Time
  
        NOTE: The above registry key is one path; it has been wrapped for
        readability.
  
     7. Open the value TZI in your time zone key to get into the binary
        editor.
  
     8. You should see binary information like this:
  
        A8FDFFFF00000000C4FFFFFF0000030000000100020000000000000000000
        A00000005000200000000000000
  
        NOTE: The above binary information is one line; it has been wrapped
        for readability.
  
     9. Change this value to the following value:
  
        A8FDFFFF00000000C4FFFFFF0000030000000500020000000000000000000
        A00000005000200000000000000
  
        NOTE: The above binary information is one line; it has been wrapped
        for readability.
  
     10. Quit Registry editor and restart you computer.
  
     11. The system should now end Daylight Savings Time on the last Sunday
         in March.
  
  

• You can also make the necessary registry changes using Regini.exe from the resource kit in conjunction with a text file that contains the following entries:

  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion \Time zones\Cen. Australia Standard Time TZI = REG_BINARY 0x0000002c 0xfffffdc6 0x00000000 0xffffffc4 0x00030000 0x00050000 0x00000002 0x00000000 0x000a0000 0x00050000 0x00000002 0x00000000

  HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion \Time Zones\Sydney Standard Time TZI = REG_BINARY 0x0000002c 0xfffffda8 0x00000000 0xffffffc4 0x00030000 0x00050000 0x00000002 0x00000000 0x000a0000 0x00050000 0x00000002 0x00000000

  Create this text file using Edit.com or Notepad with word wrap turned off. The text file can only contain ascii text characters. The key name has to be on one line, and the value on the next line, the value being spaced in 4 spaces. Save the text file using any eight-dot-three standard name you like. Then use regini as per the example below.

  Example:

  regini <filename>

  This will automatically make the necessary changes for you.

STATUS

Microsoft has confirmed this to be a problem in Windows NT versions 3.51 and 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.