Changing the system date, time and/or time zone
By default, only Administrators and Power Users can use the “Date and Time” applet to change the computer’s date, time, or time zone. A regular User double-clicking on the clock in the notification area of the taskbar gets only an error message that says, “You do not have the proper privilege level to change the System Time.” This is probably the #1 annoyance for people who have tried running as non-admin.
KB article 300022 describes how to allow non-admins to change the date, time or time zone. The KB’s first suggestion is that you ask to be made an admin or Power User. Please don’t do that. That’s kind of like saying, “I occasionally need change for a dollar, so please grant me unfettered access to the US Mint.” Fortunately, the KB also describes more granular modifications.
First, you need to have the “Change the system time” privilege. Run “Local Security Settings” (as admin), navigate in the left pane to Security Settings \ Local Policies \ User Rights Assignment. Double-click on “Change the system time” and add users or groups. You can also specify “INTERACTIVE”, which will allow whoever is logged on to the computer to change the date and time. You need to log off and back on for the change to take effect.
That gets you past the error message, and lets you change the date and the time. However, attempts to change the time zone will fail silently, with no error message. To change the time zone, you need to change the permissions on this registry key:
According to my testing, here are the permissions you need: Query Value, Set Value, Create Subkey, Enumerate Subkeys, Notify, Read Control. KB 300022 says to grant “Delete” also, but as far as I can tell, that does not appear to be necessary. This change doesn’t require logoff/logon to take effect.
[Update March 1 2005: KB 300022 has now been updated. It no longer recommends that the user be added to Administrators or Power Users, and it removed its requirement for "Delete" permission on the TimeZoneInformation regkey.]