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Article ID: 148950 - Last Review: February 28, 2014 - Revision: 2.1

This article was previously published under Q148950
This article has been archived. It is offered "as is" and will no longer be updated.


When you use NET USE or NET VIEW across a Dial-On-Demand router or slow link and the connection attempt is longer than 45 seconds, a "Semaphore Timeout" error message appears.


By default, the Windows NT redirector time-out value is 45 seconds, which limits the length of time a connection is made. To change the redirector time-out value, do the following:

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.
  1. Start Registry Editor (REGEDT32.EXE) and locate the following Registry subkey in the HKEY_LOCAL_MACHINE subtree:

  2. From the Edit menu, select Add Value.
  3. Enter the following:

    Value Name: ConnectMaxTimeout
    Data Type: REG_DWORD
    Data: <Number of seconds>
  4. Click OK and quit the Registry Editor.
  5. Shut down and restart Windows NT.

  • Microsoft Windows NT Workstation 3.5
  • Microsoft Windows NT Workstation 3.51
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 3.5
  • Microsoft Windows NT Server 3.51
  • Microsoft Windows NT Server 4.0 Standard Edition
kbnosurvey kbarchive kbnetwork KB148950
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