The Windows Redirector May Cancel a Session During a Long-Lasting Locking Operation

The Windows Redirector may incorrectly cancel a session during a long-lasting locking operation. This problem may occur when two clients access the same file on a server, where the following conditions are true:

• "Client A" locks a file on the file server.
• "Client B" also tries to lock the same file by calling the LockFileEx (hFile,LOCKFILE_EXCLUSIVE_LOCK) function.
• The file server never returns the server message block call to client B because client A still has the file locked.
• The client B Redirector times out and disconnects the session. (The time-out period is controlled by the
  Sesstimeout
  registry setting.)

This problem may occur if the LOCKFILE_FAIL_IMMEDIATELY flag in the LockFileEx function is not set and if the server returns the server message block only when the file has been successfully locked. If this takes longer than the client-side session time-out, the client's Redirector cancels the connection.

Hotfix Information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

No prerequisites are required.

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.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.