Microsoft small business knowledge base

Article ID: 267934 - Last Review: March 1, 2007 - Revision: 3.5

This article was previously published under Q267934
For a Microsoft Windows XP version of this article, see 315244  ( ) .
This article applies to Windows 2000. Support for Windows 2000 ends on July 13, 2010. The Windows 2000 End-of-Support Solution Center ( is a starting point for planning your migration strategy from Windows 2000. For more information see the Microsoft Support Lifecycle Policy ( .


When you map a network drive to a local share, the following warning message may be reported in the system event log:
Event ID: 3019
Source: MRxSmb
Description: The redirector failed to determine the connection type.


This message can occur when NetBIOS over TCP/IP (NetBT) attempts to query the target device (in this case, the Loopback adapter) for network speed. The Loopback adapter, which does not handle speed negotiation, cannot negotiate the speed and the warning message is reported in the system event log.

This behavior only occurs with the TCP/IP protocol since TCP/IP is the only protocol that uses the Loopback adapter.


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


This warning message is informational only and can be safely ignored.

This event is logged the first time you access a mapped drive and create a new session with the server. The message can also occur when you create a network connection to a share on your local computer. Therefore, the event can occur in any of the following situations:
  • The first time you access a mapped drive after you log on.
  • The first time you access the mapped drive after the computer resumes from hibernation mode.
  • The first time you access a local network share after the computer has been automatically disconnected from the mapped drive (by using the autodisconnect feature).
For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
138365  ( ) How the Autodisconnect Works in Windows NT

  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition
kbbug kbenv kbpending KB267934
Additional support options
Ask The Microsoft Small Business Support Community
Contact Microsoft Small Business Support
Find Microsoft Small Business Support Certified Partner
Find a Microsoft Store For In-Person Small Business Support