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Definition of the RunOnce Keys in the Registry
Article ID: 137367 - View products that this article applies to.
This article was previously published under Q137367
For a Microsoft Windows XP version of this article, see 314866
There are seven Run keys in the registry that cause programs to be run automatically:
Keys 1 through 7 apply to Windows 95, Windows 98, Windows 98 Second Edition, and Windows Millennium Edition (Me).
Keys 1 through 4 also apply to Windows NT 4.0 and Windows 2000.
For Windows 98, Windows 98 Second Edition, Windows Me, Windows NT 4.0 SP3 or later, and Windows 2000, an additional rule is available; for keys 3 and 4, the value name can be prefixed with an asterisk to force the program to run even in Safe mode.
Keys 1 through 4 are run each time a new user logs in.
Keys 5 and 6 are run in the background when the logon dialog box first appears, or at this stage of the boot process if there is no logon. These keys are for background services such as remote registry service and are run only once per boot.
Key 7 is run as part of Setup's first-boot activities, or after you use the Add/Remove Programs Wizard.
Under each of these keys is a series of values. The values are used to allow multiple subentries to exist without overwriting one another.
The data value for a value is a command line. By default, Run keys are ignored in Safe mode. For keys 3 and 4, the value name can be prefixed with an exclamation point to defer deletion of the value until after the command has been completed.
For keys 3, 4, and 6, the value is deleted before the command line is run unless overridden as noted above. As a result, if a RunOnce operation fails to run properly, the component that failed will not be asked to run again the next time you start the computer.
Key 7 is used only by Setup. This key displays the progress dialog box as the keys are run one at a time. For key 7, the name of the value is the name that is displayed in the dialog box.
Article ID: 137367 - Last Review: January 19, 2007 - Revision: 2.3