Changes in IRP Stack Size in Lanman Server (198386)

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows Registry

CAUSE

Depending on the hardware configuration of a specific computer, the default value may not be large enough for the Srv service to properly administer shared directories on some of the physical drives. You may see one or both of the following event messages:

   Event ID: 2011  Source: Srv
   The server's configuration parameter "irpstacksize" is too small for
   the server to use a local device.  Please increase the value of this
   parameter.

   Event ID: 0
   Source SRV
   Description:  Description for Event ID 0 could not be found.  It
   contains the insertion string \device\LanManServer

You may receive one of the above error message when a Windows NT client tries to access certain shared directories on such a server.

When a Windows for Workgroups client tries to access the same shared directories, the following message will be generated:

Path not found.

RESOLUTION

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition or the individual software update. For information on obtaining the latest service pack, please go to:

http://www.microsoft.com/windows/servicepacks/ -or-
152734 how to obtain the latest windows nt 4.0 service pack

For information on obtaining the individual software update, contact Microsoft Product Support Services. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://support.microsoft.com/directory/overview.asp

Service Pack (SP) 5 sets a minimum allowed of 7. It ignores all smaller values, and sets a default of 7 if none is specified.

SP6 sets a minimum allowed of 7. It ignores all smaller values and sets a default of 11 if none is specified.

WORKAROUND

To work around this problem, modify the registry by using the following information.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

The registry value IRPstackSize, which may be listed at

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer
   \Parameters

defaults to 0x4 if the value is not explicitly present. Valid values range from 0x1 to 0xC (1 to 12).

To increase the value of the parameter when it is not already present, go to the key:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services
   \LanmanServer\Parameters

NOTE: The above registry key is one path; it has been wrapped for readability. For the IRPStackSize change to take effect, the Server has to be rebooted.

The value of IRPStackSize defaults to 0x4 if it is not explicitly present. If the key is not present, click Add Value in Registry Editor. The Value Name should be IRPStackSize and the Data Type is REG_DWORD.