RunOnce Registry Key Runs Program at Every Startup

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, you should first make a backup copy of the registry files (System.dat and User.dat). Both are hidden files in the Windows folder.

When you use System Policy Editor to have a program run once by placing it in the RunOnce registry key on the default computer or a particular computer, the program may run every time a user logs on.

With system policies, every time a user logs on to a computer the policy file is downloaded and added to the registry. Therefore, the value is always placed in the RunOnce key at startup.

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

NOTE: For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

To cause a program to run only once, use one of the following methods:

• Use Remote Registry to open each computer's registry file, and place the program in the RunOnce key.
• Create an initial policy file with the RunOnce key enabled. After users have downloaded the change, edit the policy file to remove the RunOnce entry.
• Export and send the registry entry to users in e-mail. Users can double-click the .reg file to add the key to their registry. The program runs the next time the computer is started.

The RunOnce key is designed to cause a value to be executed only one time. When you select the RunOnce key in System Policy Editor, the value you add is placed under the following registry keys: With system policies, every time a user logs on to a computer the policy file is downloaded and added to the registry. Therefore, the value is always placed in the RunOnce key at startup.

For information about installing Remote Administration Services, please see the following article in the Microsoft Knowledge Base: