Troubleshooting Windows authentication with the Microsoft account lockout and management tools

This content is 19 years old. I don't routinely update old blog posts as they are only intended to represent a view at a particular point in time. Please be warned that the information here may be out of date.

A few weeks back I was at a Microsoft TechNet UK event where John Howard demonstrated the free tools provided by Microsoft to troubleshoot and diagnose account lockout and management issues for Windows NT, 2000 and 2003:

  • acctinfo.dll (also included with the Windows Server 2003 resource kit tools) is installed using the regsvr32 acctinfo.dll command and extends the functionality of the Active Directory users and computers MMC snap-in, with an Additional Account Info page on the user object properties to assist in isolating and troubleshooting account lockouts and to change a user’s password on a domain controller in that user’s site. This extra page contains a variety of information, including:
    • The last time the password was set.
    • Domain password policies.
    • Password expiration date.
    • Lockout status.
    • Last good and bad logons.
  • alockout.dll can be used to create a log file to assist in diagnosing the cause of account lockout problems. It should be copied to the %systemroot%\system32 folder on the computer experiencing the lockout problems (usually a user’s workstation) and the appinit.reg script run to add alockout.dll to the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs key. Once the computer is restarted and an account locked out, a log file called alockout.log will be created in the %systemroot%\debug folder. This tool should not be used on servers that host network applications or services (in particular it should not be used on Exchange servers, because it may prevent the Exchange store from starting).
  • aloinfo.exe displays the password age for user accounts to allow determination of accounts which are about to expire in order to anticipate problems before they occur. It is a command prompt tool, with two options:
    • aloinfo /expires /server:servername returns a list of user names followed by the age of their password.
    • aloinfo /stored returns a list of services and the accounts used as well as mapped drives for the currently logged on user.
  • enablekerblog.vbs can be used as a startup script to enable Kerberos logging (as described in Microsoft knowledge base article 262177) on all clients running Windows 2000 or later (it actually sets HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\LSA\Kerberos\Parameters\LogLevel to 1, which once removed will disable Kerberos logging). When looking at Kerberos authentication issues, it is worth checking to see that the Kerberos key distribution center service is started on all domain controllers, that time synchronisation is working correctly from the PDC emulator at the root of the forest down to all client machines (Kerberos authentication will fail if the time is skewed by more than 5 minutes by default), and that both Kerberos and LDAP have service location records defined in DNS (check with nslookup _kerberos._udp.domainname and nslookup _ldap._tcp.domainname).
  • eventcombmt.exe (also included with the Windows Server 2003 resource kit tools) searches event logs on multiple computers and collects event records matching specified criteria (useful for gathering specific events from event logs on several different computers to one central location).
  • lockoutstatus.exe (also included with the Windows Server 2003 resource kit tools) determines all the domain controllers that are involved in a lockout of a user in order to assist in gathering the logs. It can be useful in identifying if lockout problems are arising from Active Directory replication issues, as typically this means there will be two or more entries for different domain controllers.
  • nlparse.exe can be used to extract and display desired entries from the netlogon log files generated by lockoutstatus.exe or alockout.dll, parsing the logs for specific return status codes and directing the output to a comma-separated value (.CSV) file. It is also possible to enable netlogon debug logging with the nltest.exe Windows support tool, or via the registry, as described in Microsoft knowledge base article 109626.


Implementing and troubleshooting account lockout (
Microsoft account lockout and management tools.

One thought on “Troubleshooting Windows authentication with the Microsoft account lockout and management tools

  1. Take a look at NetWrix Account Lockout Examiner ( – this tool automatically determines the reason for account lockout (by scanning different places where old user password can be stored). We use this tool in our network to troubleshoot account lockouts when account lockout reason can not be determined manually.

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