Registry Settings for Event Detail in the Dcpromoui.log File

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256986 Description of the Microsoft Windows Registry


Dcpromo builds two log files (Dcpromoui.Log and Dcpromo.log) in the %SystemRoot%\Debug folder on Windows 2000-based servers. Both files are useful for troubleshooting problems with the promotion or demotion of Active Directory servers.

This article describes registry settings that control the log detail in the Dcpromoui.log file.


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The Dcpromoui.log file captures status information on the promotion or demotion of an Active Directory computer from start to finish, including the capture of user input for the role the server will play in the forest.

Logging detail in the Dcpromoui.log file is controlled by the DCPROMOUI setting. To increase or decrease the logging detail captured, set the bit mask for the DCPROMOUI registry entry using the bit mask definitions shown below. Modify the data value for the DCPROMOUI (REG_DWORD) value in the following registry key:


The DCPROMOUI value is a bit mask. The high word is a mask of logging levels:

0x0002 Trace constructor and destructor calls 0x0004 Trace AddRef and Release calls 0x0008 Trace function entry and exit 0x0010 Output trace messages 0x0020 Output log header with build and time stamp 0x0040 capture the call stack for each invocation of operator new (chk build only)

The low word is a mask of output options:

0x0001 Output to file in the %SystemRoot%\Debug folder 0x0002 Output to debugger (OutputDebugString)

To enable maximum logging detail to the %SystemRoot%\Debug\Dcpromoui.log file and debugger, set the DCPROMOUI bitmask to 0xFF0003. (Enter "FF0003" and not the leading "0x" characters.)

The current log mask setting can be displayed by searching for the "logging mask" string in the Dcpromoui.log file (typically the fourth line from the top of the file). A DCPROMOUI setting of 0xFF0003 is displayed as logging mask 00FF in the Dcpromoui.log file.