If you don't use the built-in Windows Calendar or use it to display your Google calendar, you might be interested in removing the application from Windows Vista.

Unfortunately, Microsoft doesn't give us a good way to completely remove it, so we'll have to do the next best thing and use system policies to disable it.

You'll still see the icon in Windows Mail even afterwards, however:

When you click on the button, you'll get this error message indicating that we disabled it.

At least we can remove it from most everywhere else.

Manual Registry Hack

To make this change, type in regedit.exe into the start menu search box, and then browse down to the following key, creating the key if it doesn't exist.

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Windows

Create a new 32-bit DWORD value named TurnOffWinCal and give it a value of 1.

Remove From Start Menu

Paste the following into the address bar in Windows Explorer, and then browse down into the Programs folder.

shell:Common Start Menu

You'll see the shortcut for Windows Calendar, which you can delete to remove it from the Start menu.

If you've deleted this shortcut and want to re-enable it, you'll have to manually create a shortcut to wincal.exe in this folder.

Download Registry Hack

Download TurnOffWinCal.zip, unzip and double-click on TurnOffWinCal.reg to disable Windows Calendar through group policy. You can also use the TurnOn registry hack to put things back to normal.