POP3 and IMAP Clients Are Not Authenticated on Exchange Server 2000

Article translations Article translations
Article ID: 272492 - View products that this article applies to.
This article was previously published under Q272492
This article has been archived. It is offered "as is" and will no longer be updated.
Expand all | Collapse all


When the Exchange Server 2000 registry key HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA has the LmCompatibilitylevel value set to 5, POP3 and IMAP clients are not authenticated.


This issue occurs because the 5 value does not allow a check for clear text passwords, and authentication therefore does not work properly.


A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem.

To resolve this problem, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
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.

The English version of this fix should have the following file attributes or later:
   Date         Time   Size     File name     Platform
   25-Sep-2000  21:07  247,056  Advapi32.dll  x86
   25-Sep-2000  21:08   48,400  Msv1_0.dll    x86

   25-Sep-2000  21:06  403,728  Advapi32.dll  Alpha
   25-Sep-2000  21:06   79,632  Msv1_0.dll    Alpha


Microsoft has confirmed that this is a problem in Windows NT 4.0.


Article ID: 272492 - Last Review: November 1, 2013 - Revision: 3.0
Applies to
  • Microsoft Windows NT Server 4.0 Standard Edition
  • Microsoft Windows NT Server 4.0 Enterprise Edition
  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Exchange 2000 Server Standard Edition
kbnosurvey kbarchive kbbug kbfix kbqfe kbhotfixserver KB272492

Contact us for more help

Contact us for more help
Connect with Answer Desk for expert help.
Get more support from smallbusiness.support.microsoft.com