Although many people use the Date/Time control panel to flip through a calendar, that's not what it is for. In fact, if you use it that way, you can create all sorts of havoc!

In its original incarnation in Windows 95, the Date/Time control panel changed your date and time. If you clicked through the calendar to see next month, you actually changed your system clock to next month. If you changed your mind and clicked "Cancel", the Date/Time control panel undid its changes and restored the date to the original date.

In other words, here's what happened, step by step:

  • On April 1, you open the Date/Time control panel.
  • You change the month to May. The Date/Time control panel changes your system date to May 1. If you are running an appointment calendar program, all appointments from the month of April will fire. (For example, your April 15th alarm to remind you to file your income taxes.) You are annoyed by all these alerts and you cancel them.
  • You decide you didn't want to change the month to May after all and click Cancel.
  • The Date/Time control panel changes the date back to April 1.
  • On April 15th, your income tax alarm fails to fire because you cancelled it, remember?

In other words, the Date/Time control panel was not designed for letting you flip through a calendar. It was designed for changing the system date and time.

Unaware of its design, people have been using the Date/Time control panel as if it were a calendar, not realizing that it was doing all sorts of scary things behind the scenes. It's like using a cash register as an adding machine. Sure, it does a great job of adding numbers together, but you're also messing up the accounting back at the main office!

For Windows 2000, in reluctant recognition of the way people had been mis-using the Date/Time control panel, it was rewritten so that it doesn't change the system time until you hit the Apply button.

Aaron Margosis shows you how to grant a user permission to change the system date and time without having to make them a full administrator.