Export (0) Print
Expand All


Updated: March 28, 2003

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2



The ControlSet00n subkeys represent a control set for the system.

The numbered ControlSet00n subkeys, such as ControlSet001 and ControlSet002, contain control sets that can be used to start and run Windows Server 2003. Most systems have two numbered control sets (an original and a backup copy) of a control set that has been used to start the system successfully, but the system can maintain as many as four control sets. Windows Server 2003 maintains backup copies so that you can undo configuration changes that might otherwise prevent you from starting the system.

Windows Server 2003 identifies the control set that was last used successfully, the current control set, and the default control set. These designations are stored in the Select subkey.

Windows Server 2003 automatically maintains the control sets and selects one of them when the system starts. It bases this selection on settings in the Select subkey and on the success or failure of system startup. Users can specify the LastKnownGood control set by pressing the F8 key on the OS Choices Menu during system startup to display the Advanced Startup Options menu.

All the numbered control set subkeys, including the one that appears in the CurrentControlSet subkey, can have the same subkeys and entries. In this reference, these subkeys are entries listed in the CurrentControlSet subkey.


  • The ControlSet00n subkey is a variable representing the numbered control sets in the HKLM\SYSTEM key. It does not actually appear in the registry.

See Also

Was this page helpful?
(1500 characters remaining)
Thank you for your feedback

Community Additions

© 2015 Microsoft