The Log File Debug Output Level machine setting should be configured correctly. Specifies the level of debug output for the Net Logon service. The Net Logon service outputs debug information to the log file netlogon.log in the directory %windir%\debug. By default, no debug information is logged. If you enable this setting and specify a non-zero value, debug information will be logged to the file. Higher values result in more verbose logging; the value of 536936447 is commonly used as an optimal setting. If you specify zero for this setting, the default behavior occurs as described above. If you disable this setting or do not configure it, the default behavior occurs as described above. Fix: (1) GPO: Computer Configuration\Administrative Templates\System\Net Logon\Log File Debug Output Level (2) KEY: HKLM\Software\Policies\Microsoft\Netlogon\Parameters\dbFlag