Changes in IRP Stack Size in Lanman Server

When you access shares on a computer running Windows NT Server from a Windows NT client and the IRPstackSize parameter is set too low on the server, you may receive the following error message:

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:

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:

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/downloads/details.aspx?familyid=E396D059-E402-46EF-B095-A74399E25737&displaylang=en/ (http://www.microsoft.com/downloads/details.aspx?familyid=E396D059-E402-46EF-B095-A74399E25737&displaylang=en/) -or-
  
  
• 152734  (http://support.microsoft.com/kb/152734/EN-US/ ) 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:
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.

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

Important 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:

The registry value IRPstackSize, which may be listed at

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:

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.

Microsoft has confirmed that this is a problem in Windows NT 4.0 and Windows NT Server 4.0, Terminal Server Edition. This problem was first corrected in Windows NT 4.0 Service Pack 4.0 and Windows NT Server 4.0, Terminal Server Edition Service Pack 4.