A disk may not come online if only non-optimized paths are available on Windows Server 2008 and Server 2008 R2

Symptoms
Consider the following scenario:
In an MPIO/ALUA configuration on Windows Server 2008 and Server 2008 R2 where only non-optimized paths are available, a disk may not come online.
Resolution
This occurs because the default MPIO policy for ALUA capable controllers when using the Microsoft DSM is Round Robin with Subset (RRwS), and this policy does not allow a disk to come online without an optimized path being available.

When you try to access files on a network share, Windows Explorer stops responding on a computer that is running Windows 7, Windows Server 2008 R2, Windows Vista or Windows Server 2008

Symptoms
Consider the following scenario:You have a network share that is hosted on a computer that is running Windows Server 2008 or Windows Server 2008 R2 in a network environment.You map a drive to the network share on a client computer that is running Windows 7, Windows Server 2008 R2, Windows Vista or Windows Server 2008.You open some applications to query the extended attributes of the files on the network share. You open Windows Explorer and then click the mapped drive to browse the files.In this scenario, Windows Explorer stops responding for about 35 seconds.
Resolution
This issue occurs because of the file control block (FCB) resource being locked unexpectedly before the client sends the CreateFile and QueryInformation requests to the server. Therefore, the client cannot handle the Oplock break notification request that is returned by the server. This behavior causes Windows redirector to temporarily stop responding.

The memory usage for the Csrss.exe process keeps increasing if a drive letter is frequently changed

Symptoms
The memory usage of the Csrss.exe process keeps increasing if a drive letter is frequently changed on a computer that is running Windows Server 2008 or Windows Vista.
Additionally, you encounter one or more of the following symptoms:The logs for the Performance Monitor indicate that the Private Bytes counter for the Csrss.exe process keeps increasing.The performance of the computer is poor or the computer stops responding. To recover from this issue, you have to restart the computer.
Resolution
When a driver letter that is related to a network drive mapping, to a local volume mount, or to a local volume unmount is changed, a new thread starts in the Csrss.exe process. This thread sends out a broadcast that a drive letter for a drive has changed. After it sends the broadcast, this thread exits. However, some allocated memory is not freed when the thread exits. Therefore, you encounter the issue that is described in “Symptom” section when the drive letter is frequently changed.

How to enable COM+ and COM diagnostic tracing

Symptoms
Event Tracing for Windows (ETW) provides a mechanism to trace and log events that are raised by user-mode applications and kernel-mode drivers. In Windows Server 2003 Service Pack 2 (SP2), in Windows Vista, or in newer Windows operating systems, you can use ETW to trace events for some COM+ components and for some base COM components. COM tracing can help you troubleshoot issues that are related to permission, activation, or registration.
The tracing mechanism produces a binary file. The binary file must be formatted by Microsoft so that it can be analyzed.
You can trace the following COM+ and COM providers: COMSVCS COMADMINDCOMSCM (RPCSS) OLE32This article describes how to enable and collect diagnostic trace output for COM+ and COM components in Windows Server 2003 SP2, Windows Vista, and newer Windows operating systems.
Resolution
Start tracing for the COMSVCS, COMADMIN, and DCOMSCM providers To start the tracing for COMSVCS, COMADMIN, and DCOMSCM providers, run one ofthe following commands as appropriate at the command prompt:
logman -start comsvcs -p {B46FA1AD-B22D-4362-B072-9F5BA07B046D} 0xf 0×5 -ets
logman -start comadmin -p {A0C4702B-51F7-4ea9-9C74-E39952C694B8} 0xf 0×5 -ets
logman -start dcomscm -p {9474a749-a98d-4f52-9f45-5b20247e4f01} 0×7 0×5 -etsStart tracing for the OLE32 providerImportant This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756
(http://support.microsoft.com/kb/322756/) How to back up and restore the registry in Windows By default, OLE32 tracing is not enabled. Therefore, you must enable OLE32 tracing before you can start tracing. You can do this by adding the required registry entries as described in this section. You can enable OLE32 tracing on all processes that use OLE32 or on specific processes. OLE32.dll is loaded in many processes, and enabling tracing for all processes may cause decreased performance. Therefore, we do not recommend enabling tracing for all processes.At the command prompt, run the following command to enable OLE32 tracing on all the processes that use OLE32:
reg add HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\Tracing /v ExecutablesToTrace /t REG_MULTI_SZ /d * /fAt the command prompt, run the following command to enable OLE32 tracing on specific processes that use OLE32:
reg add HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\Tracing /v ExecutablesToTrace /t REG_MULTI_SZ /d “c:\test\app1.exe\0c:\test\app2.exe” /fNote You can type multiple executables in the registry value. You must type the full path of each executable. Notice the use of double quotation marks and the null terminator (\0).After enabling OLE32 tracing, you must restart the process for the change to take effect.
After you enable OLE32 tracing,start the tracing by running the following command at the command prompt:
logman -start ole32 -p {bda92ae8-9f11-4d49-ba1d-a4c2abca692e} 0xf 0×5 -etsStop tracing for all providersImportant You must stop the tracing so that the buffer is written to disk. To do this, run one of the following commands as appropriate at the command prompt:
logman -stop comsvcs -ets
logman -stop comadmin -ets
logman -stop dcomscm -ets
logman -stop ole32 -etsLog file location The start command will create a log file that has an .etl extension, such as Dcomscm.etl, Ole32.etl, and so on, in the current directory. You can use the -o option to change the output path when you run the start command.Next StepsThe binary file must be formatted by Microsoft so that it can be analyzed. Please forward the .etl files to your support contact. For more information about how to contact Microsoft Customer Service and Support, click the following article number to view the article in the Microsoft Knowledge Base:
295539
(http://support.microsoft.com/kb/295539/) How and when to contact Microsoft Customer Service and SupportDelete the registry key after the trace session is completed.At the command prompt, run the following command to disable OLE32 tracing on all the processes that use OLE32:
reg delete HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\Tracing /v ExecutablesToTrace /t REG_MULTI_SZ /d * /fAt the command prompt, run the following command to disable OLE32 tracing on specific processes that use OLE32:
reg delete HKEY_LOCAL_MACHINE\Software\Microsoft\OLE\Tracing /v ExecutablesToTrace /t REG_MULTI_SZ /d “c:\test\app1.exe\0c:\test\app2.exe” /f

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