Microsoft states in their article: 824909

Deadlock condition may occur when a large number of DFS clients connect to a shared folder for the first time
View products that this article applies to.
Article ID : 824909
Last Review : February 27, 2006
Revision : 7.0
On This Page
SYMPTOMS SYMPTOMS
CAUSE CAUSE
RESOLUTION RESOLUTION
Hotfix information Hotfix information
Prerequisites Prerequisites
Restart requirement Restart requirement
Hotfix replacement information Hotfix replacement information
File information File information
STATUS STATUS
MORE INFORMATION MORE INFORMATION
APPLIES TO APPLIES TO
SYMPTOMS
When many Distributed File System (DFS) clients connect to a server and access a shared folder for the first time, you may find that a deadlock condition occurs in the server message block (SMB) redirector component or in the Terminal Services redirector component. Therefore, the server does not return a referral to the DFS client, and the DFS client cannot connect to the shared folder.

For example, a deadlock condition in the Terminal Services redirector component may result when many DFS clients connect to the server in a Terminal Services session and access different \\ServerName\ShareName shares, where an entry does not exist for any one of the shares in the DFS referral cache.
Back to the top Back to the top
CAUSE
This problem may occur if both the following conditions are true:
� The number of network file access requests is larger than the number of available critical worker threads.
� The network file access requests are for \\ServerName\ShareName shares that are accessed by the DFS client for the first time. That is, share entries do not exist in the DFS referral cache.
The DFS client (Mup.sys) posts network file access requests to the critical work queue on the server. Because the DFS client does not throttle work items, a deadlock condition may occur in situations where the redirector components require worker threads to complete the transport connection operations, and the worker threads are exhausted by the DFS client.
Back to the top Back to the top
RESOLUTION
To resolve this issue, obtain the latest service pack for Windows Server 2003.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:
889100 (http://support.microsoft.com/kb/889100/) How to obtain the latest service pack for Windows Server 2003
Back to the top Back to the top
Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Windows Server 2003 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/contactus/?ws=support (http://support.microsoft.com/contactus/?ws=support)
Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.
Prerequisites
This hotfix requires Windows Server 2003.
Restart requirement
You must restart your computer after you apply this hotfix.
Hotfix replacement information
This hotfix does not replace any other hotfixes.
File information
The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

Date Time Version Size File name
-------------------------------------------------------
22-Jul-2003 19:10 5.2.3790.71 106,496 Mup.sys
22-Jul-2003 18:58 5.2.3790.71 304,640 Mup.sys IA-64

Back to the top Back to the top
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section of this article. This problem was corrected in Windows Server 2003 Service Pack 1.
Back to the top Back to the top
MORE INFORMATION
For more information about DFS in Windows Server 2003, visit the following Microsoft Web site:
http://technet2.microsoft.com/windowsserver/en/library/20ffb860-f802-455...