UserEnv experienced an error applying Group Policy to the domain controller. Group Policy must be applied successfully for domain controllers to function properly because domain controllers get several critical permissions, such as Access this computer from network, through policy.
Because of the architecture of UserEnv, Microsoft Operations Manager (MOM) is unable to directly report the specific problem.
Windows cannot find the machine account, %1.
Possible causes include:
The computer has been restarted. If it is determined that this was the cause of the alert, simply resolve the alert.
The computer might be running out of available memory.
For more information, see the UserEnv log file. UserEnv logging is not enabled by default. To enable UserEnv logging, see article 221833, “How to enable user environment debug logging in retail builds of Windows,” in the Microsoft Knowledge Base at http://go.microsoft.com/fwlink/?LinkId=25636. The log file provides details about the specific error.
Microsoft Help and Support for Microsoft Windows Server 2003
Microsoft Knowledge Base