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Home»Product Support»DAYLIGHT SAVINGS TIME»PC / Windows Operating Systems


Many PC-based access control solutions use the PC`s date and time settings to keep the access panels up to date. When the PC changes times due to Daylight Savings, the panels are updated either manually or automatically. It becomes important therefore to be sure these access control PCs remain accurate to the new rules for Daylight Savings time.
Often the PCs managing an access control system are not connected to the internet, so they are unable to receive automatic updates from Microsoft. Many office and home PCs will receive an automatic update that changes Daylight Savings rules properly. Computers which do not receive automatic updates require manual updating.
Even if your access control PC is hooked up to the internet and receives automatic updates, Microsoft no longer supports Windows 95 and Windows 98 and therefore will not automatically update those operating systems. Windows 2000 machines may be updated, as may Windows XP. According to Microsoft, all Windows Vista systems will ship with the new updates already included.
Because Windows PCs may not have the Daylight Savings Time rules properly and automatically updated, a manual update solution is possible. This solution works on all Windows PCs from Windows 95 through Windows XP. Microsoft has provided this update, and we provide a copy of it here to assist those unable to automatically update their PCs. The update must be applied once only, and will then work for this year and any year in the future.
  • Download the archive file tzedit.zip. If you prefer you can download the archive file from Microsoft. Unzip the file`s contents and copy them to the PC requiring the update.
  • Run the tzedit.exe program (The file with the globe icon).
  • The program should show a list of time zones with the currently-enabled time zone highlighted. Click the Edit button.
  • On the next screen, verify the rules for DST beginning and ending. Likely the rules will say DST begins the First Sunday of April at 2:00 AM, and ends on the Last Sunday of October at 2:00 AM.
  • Change the rules. DST now begins on the Second Sunday of March at 2:00 AM, and ends on the First Sunday of November at 2:00 AM.
  • You do not need to change the Time Zone Name, the Abbreviation, the Offset from GMT, or the Daylight Bias. Ensure that "Automatically set Daylight Savings Time" is checked, and click OK. You can then close the program.
  • Your system is now up to date and will properly update the times for Daylight Savings! You will only have to make these changes once, and the system will update properly this year and in the future.
This information has been derived from a Microsoft document listed as Windows: Preparing for daylight saving time changes in 2007. Windows does not support the use of this utility program and recommends the use of Windows Update on a current Operating System platform, but provides the tzedit.exe program to allow manual updates such as are advised above. If for whatever reason you are unable to successfully update a PC`s automatic Daylight Savings Time settings, be advised you should have the automatic DST adjustment turned off so it does not change times on the wrong date, and you will have to adjust the PC`s time settings manually at the appropriate times.