Article ID: 843584 - View products that this article applies to.
You work with Microsoft ASP.NET or Microsoft Active Server Pages (ASP) that are stored on a remote file share that uses the Server Message Block (SMB) protocol. When more SMB requests exist than the Web server can process, your Web application may unexpectedly restart or you may lose the session object. When this problem occurs, you may receive the following error message in the error log:
Note Remote file shares that use the SMB protocol can include Network Attached Storage (NAS) devices, System Area Networks (SAN), or UNIX-based shares.
Failed to start monitoring directory changes.
This problem occurs when the number of SMB requests to the server is larger than the resources that are allocated to handle the requests. If the SMB redirector receives too many network requests, you may lose the session object, your application may restart, and you may receive an error message in the error log.
Note This problem may occur because of server load or the remote file share load. To verify that the load on the server is the problem, click Start, click Run, type perfmon, and then click OK. Then, if the value of the Redirector/Current Commands entry is more than 90 percent of the maximum load value, raise the capacity of the server.
This problem may occur when the number of SMB requests outnumber the resources to handle those requests, or it may occur when the number of SMB requests on the file share outnumber the resources to handle those requests.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
To work around this problem, increase the number of connections that you can have by resetting the registry values of the
MaxMpxCtsubkeys. The recommended values are 253, 1124, and 2048. To do this, follow these steps.
Note In this section, the LanmanWorkstation is the Web server and the LanmanServer is the remote share.
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:
(https://support.microsoft.com/kb/322756/ )How to back up and restore the registry in Windows
(https://support.microsoft.com/kb/294418/ )Comparison of 32-bit and 64-bit memory architecture for 64-bit editions of Windows XP and Windows Server 2003
Note This article does not apply to x64-based computers.
For more information about SMB and about your specific hardware and software configuration, contact your vendor or service provider.
For more information about the SMB Redirector and how to raise the value of the MaxMpxCt and MaxMpx keys, click the following article numbers to view the articles in the Microsoft Knowledge Base:
(https://support.microsoft.com/kb/317249/ )How to troubleshoot Event ID 2021 and Event ID 2022
(https://support.microsoft.com/kb/810886/ )"The network BIOS command limit has been reached" error message in Windows Server 2003, in Windows XP, and in Windows 2000 Server
Article ID: 843584 - Last Review: August 11, 2009 - Revision: 3.0