Australian Time Zones End Daylight Savings Time on Wrong Date

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

Additional query words: DST

Keywords : kbsetup kbbug4.00 kbbug3.51 kbdomain NTSrvWkst
Version : WinNT:3.5,3.51,4.0
Platform : winnt
Issue type : kbbug