RDR Sessions on UNC Name Images May Log Off Prematurely

The problem occurs when multiple sessions access an image as a UNC name. When the first session to access the file logs off, the second session can no longer access the image.

Example

Thread A impersonates a user and maps a file (typically, loads an image) using a UNC name. Another thread (thread B) impersonates a different user and maps the same file. Thread A logs off and thread A's session is logged off the server. Thread B cannot access the mapped file any longer.

Because of the way RDR and memory management work, thread B is accessing the mapped file on thread A's user ID. When both threads first access the server, two separate sessions are opened, creating two separate user IDs. However, when the session object is created to access the mapped file by thread B, and because it is the same file, it uses the same file object that was opened by thread A. The file object contains session information that the redirector uses to access the remote computer; therefore, thread B accesses the file on thread A's session.

To resolve this problem, obtain the latest service pack for Windows NT 4.0 or Windows NT Server 4.0, Terminal Server Edition. For additional information, click the following article number to view the article in the Microsoft Knowledge Base:

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.