This article discusses how to enable diagnostic tracing for the Microsoft Distributed Transaction Coordinator (MS DTC) on a Windows Vista-based computer.

The following types of tracing facilities are available:

•	Transaction manager tracing Transaction manager (TM) tracing tracks transaction state changes. It is generated by the MS DTC transaction manager. The output is in binary format, and the output must be formatted. The transaction manager is part of the MS DTC service.
•	Communication manager error tracing Communication manager (CM) error tracing tracks any process that loads the Msdtcprx.dll file and that uses the remote procedure call (RPC) interface of MS DTC to communicate with other MS DTC-related processes. The output is in text format. The "0x8004d00a" error is a typical error for which communication manager error tracing may be useful.

Note Transaction manager tracing and communication manager error tracing are independent processes. You can independently enable transaction manager tracing and communication manager error tracing. Or, you can independently disable them.

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Enable transaction manager tracing

You can use the Component Services Microsoft Management Console (MMC) snap-in to enable transaction manager tracing. To do this, follow these steps:

1.	Click Start, click All Programs, click Accessories, and then click Run.
2.	Type comexp.msc, and then click OK.
3.	Expand Component Services, expand Computers, expand My Computer, expand Distributed Transaction Manager, right-click Local DTC, and then click Properties.
4.	Click the Tracing tab.
5.	On the Tracing tab, you can modify the following TM tracing options:   Trace Output   Trace Transactions • Trace All Transactions • Trace Aborted Transactions • Trace Long-Lived Transactions

When you change the TM tracing configuration, the MS DTC service detects the changes. However, you do not have to recycle the process. For example, when you change the transactions that are traced or the location of the trace file, the MS DTC service detects the change in the registry. You do not have to restart the MS DTC service.

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New MS DTC tracing system in Windows Vista

In Windows Vista, MS DTC has a new and extensive tracing system. The new system has the following design goals:

•	Only a single line of code is required to add a formatted trace.
•	The trace is readable by humans on production computers without a network.
•	Output options are flexible.
•	The trace is fast.
•	You do not have to restart the computer to change the options.

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Configure tracing

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

Trace configuration is located on the local node, in a registry key that is named Tracing under the MS DTC registry key. The Tracing registry key includes connection manager tracing. Previously, you used the TraceCMErr registry key to configure connection manager tracing. The Tracing registry key contains the following two subkeys:

•	Sources The Sources subkey configures the kind of tracing.
•	Output The Output subkey configures where the tracing output is sent.

Note Make sure that the process can access the Tracing registry key. By default, the Windows Vista configuration does not create this key and does not grant permissions to this key. You can use Registry Editor to configure tracing functionality.

To create tracing functionality registry entries, follow these steps:

1.	Click Start, click All Programs, click Accessories, click Run, type regedit , and then click OK.
2.	Locate and then click the following subkey: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\Tracing
3.	On the Edit menu, click New, and then click the data type of the entry. For example, click DWORD (32-bit) Value.
4.	Type the name of the desired source, and then press ENTER. For more information about the source names, see the table in the "Configure sources" section.
5.	Right-click the new registry entry, click Modify, type the value that you want in the Value data box, and then click OK.
6.	On the File menu, click Exit.

Configure sources

The Sources registry key contains a set of DWORD registry values that are listed in the following table.

Name	Description
TRACE_MISC	Traces that cannot be categorized into the other categories
TRACE_CM	Traces in the connection manager
TRACE_TRACE	The trace infrastructure itself
TRACE_SVC	Traces service and .exe file startup
TRACE_GATEWAY	Gateway source
TRACE_UI	Traces the user interface
TRACE_CONTACT	Traces the contact pool and contacts
TRACE_UTIL	Traces utility routines that are called from multiple locations
TRACE_CLUSTER	Traces the cluster-specific (utility) code
TRACE_RESOURCE	Traces the cluster resource-specific code
TRACE_TIP	Transaction Internet Protocol (TIP) tracing source
TRACE_XA	XA Transaction Manager (XATM) tracing source
TRACE_LOG	Log tracing
TRACE_MTXOCI	MTS/OCI layer (Mtxoci.dll) tracing source
TRACE_ETWTRACE	Event Tracing for Windows (ETW) tracing source
TRACE_PROXY	Traces that are generated in the MSDTC proxy DLL
TRACE_KTMRM	Tracing for integration with Kernel Transaction Manager
TRACE_VSSBACKUP	Tracing for integration with the Microsoft Visual SourceSafe backup and restore mechanism
TRACE_PERFMON	Tracing with support for performance counters

The DWORD value should be a number from 0 to 255. The DWORD value indicates the level of tracing that occurs. The following table lists possible DWORD values.

Value	Description
0	const BYTE TRACE_OFF
1	const BYTE TRACE_ERROR
2	const BYTE TRACE_WARNING
3	const BYTE TRACE_INFO
4	const BYTE TRACE_VERBOSE
5	const BYTE TRACE_VERY_VERBOSE
6	const BYTE TRACE_INOUT
0xF0	const BYTE TRACE_OBSCURE
0xFF	const BYTE TRACE_EVERYTHING

Note Higher values automatically include lower values. Therefore, when you enable the TRACE_INFO level, the TRACE_ERROR level is also enabled. Very few sources use any tracing that is higher than the TRACE_VERBOSE level.

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Configure trace output

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

The Output registry key contains a set of values that control where trace output is sent. These values are as follows:

•	The TraceFilePath (REG_SZ) value is the root folder in which trace files should be stored. Tracing is written to a file in a folder that is named msdtc-X.log. In this folder name, X represents the decimal PID of the process that creates the file. Make sure that all the processes of interest can access the configured folder. Otherwise, trace information will be lost. If this value is not set, traces are not sent to a file.
•	The MemoryBufferSize (REG_DWORD) value is the size of the circular buffer in which trace messages are stored. If this value is set to 0, memory tracing is disabled. By default, this value is 10 MB. You may have to increase this value if you enable verbose tracing.
•	The DebugOutEnabled (REG_DWORD) value enables or disables output to the debugger. If the value is nonzero, the output is enabled. By defaut, this Output registry key is disabled.

When you change the connection manager error-tracing configuration, the changes take effect when a process that loads the Msdtcprx.dll file is recycled. For example, the changes to the connection manager error-tracing configuration take effect when the MS DTC service process is recycled.

Alternatively, you can create a .reg file, and then you can use Registry Editor to import the file. To do this, follow these steps:

1.	Create a new .reg file that contains the following code example. Windows Registry Editor Version 5.00 [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\Tracing] [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\Tracing\Output] "DebugOutEnabled"=dword:00000000 "TraceFilePath"="" "MemoryBufferSize"=dword:0000000a [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSDTC\Tracing\Sources] "TRACE_MISC"=dword:00000000 "TRACE_CM"=dword:00000000 "TRACE_TRACE"=dword:00000000 "TRACE_SVC"=dword:00000000 "TRACE_GATEWAY"=dword:00000000 "TRACE_UI"=dword:00000000 "TRACE_CONTACT"=dword:00000000 "TRACE_UTIL"=dword:00000000 "TRACE_CLUSTER"=dword:00000000 "TRACE_RESOURCE"=dword:00000000 "TRACE_TIP"=dword:00000000 "TRACE_XA"=dword:00000000 "TRACE_LOG"=dword:00000000 "TRACE_MTXOCI"=dword:00000000 "TRACE_ETWTRACE"=dword:00000000 "TRACE_PROXY"=dword:00000000 "TRACE_KTMRM"=dword:00000000 "TRACE_VSSBACKUP"=dword:00000000
2.	Click Start, click All Programs, click Accessories, click Run, type regedit , and then click OK.
3.	On the File menu, click Import.
4.	Locate the file that you created in step 1, and then click Open. The Registry Editor dialog box appears.
5.	Click OK.
6.	On the File menu, click Exit.

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Performance effect

By default, tracing functionality is disabled in Windows Vista. Therefore, no performance effect exists on a regular installation.

You should not enable tracing functionality on production computers unless a Microsoft Customer Support Professional indicates that the tracing information is required to diagnose a problem. Tracing may affect computer performance. First you must find the problem, and you must resolve it. Then, immediately disable the tracing functionality.

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Cluster configuration

For cluster installations, make sure that all registry entries on all the nodes contain these registry entries. For any node that does not have these registry entries, the cluster code ignores the registry entries in the shared registry because the registry entries do not exist in the local computer registry.

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