Windows NT 3.51 Does Not Have Updated Daylight Saving Time

• Microsoft Windows NT Workstation versions 3.51
• Microsoft Windows NT Server versions 3.51

SYMPTOMS

Many European countries have changed the date on which they switch from daylight savings time to standard time; it was the last Sunday in September and is now the last Sunday in October. Windows NT 3.51 is currently configured to switch in September.

RESOLUTION

Follow these instructions to manually change from daylight saving time:

WARNING: Using the Registry Editor incorrectly can cause serious, system- wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of the Registry Editor can be solved. Use this tool at your own risk.

1. Locate the time zone used in the registry:

   a. Start Regedt32.exe.

   b. In the HKEY_LOCAL_MACHINE subtree find the subkey:

            SOFTWARE\Microsoft\Windows NT\CurrentVersion\Time Zones
   
      c. In the list of time zones locate the one you are using by finding the
         one that the value "Display" that matches the setting in Control
         Panel/Date/Time.
   
   

2. Modify the Time Zone Information:

   a. Open the value TZI in your time zone key to get into the binary editor.

   b. You should see binary information like this:

   The values "C4FFFFFF" are dependent on the offset from Greenwich time,
   so you may see different values than those shown above.

   c. On the first line, move the cursor to the vertical line between c and
   10. Change the character "9" right next to it to the character "A".

   d. Click OK.