In Windows 2000, the Event Log service may stop logging events before the size that is specified in the Maximum log size setting is reached if the Do not overwrite events option is turned on. This can cause events to be lost.
The event log generally stops logging new events when the log reaches a size of from approximately 200 megabytes (MB) to 600 MB.
The Event Log service may report that the event log is full and stop logging events before the maximum log size is reached. If the "Shut down system immediately if unable to log security audits" Group Policy setting is in use on a computer, the computer may stop auditing events and may stop responding (hang) sooner than expected.
Service pack information
To resolve this problem, obtain the latest service pack for Windows 2000. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
260910 How to obtain the latest Windows service pack
A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.
If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.
Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site:
Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.
Date Time Version Size File name -------------------------------------------------------- 02-May-2002 14:28 5.00.2195.5722 45,328 Eventlog.dll
With this fix installed, you can implement an automatic backup process (by using a registry key) when the current event log cannot be extended. You can add a registry key for each event log to increase the time before the event log becomes full, or before the computer hangs. Note that the size of the event logs is still limited by the available resources on the computer (such as virtual memory and free disk space).
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section. This problem was first corrected in Microsoft Windows 2000 Service Pack 4.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
To use the new automated backup behavior after you apply this hotfix, you must add registry keys such as the following keys:
Value: AutoBackupLogFiles Type: DWORD Data value: Value not present or 0 (zero) equals "disabled." (This is the default.) Any non-zero value equals "enabled."
Note You must restart the computer or clear the corresponding event log before the new behavior takes effect. You must configure the event log to have the Do not overwrite events (clear log manually) setting.
If you are using the "Shut down system immediately if unable to log security audits" (CrashOnAuditFail) policy and if you do not clear the security log after you set the Security registry value to 1, the computer still stops responding when an audit failure occurs.
Description of the AutoBackupLogFiles registry entry
Using this entry causes the Event Log service to automatically clear a full event log and to back up the log file. On computers with the "CrashOnAuditFail" policy turned on, the computer continues to log events (instead of hanging because of an audit failure) if the current log file can be backed up automatically. By default, event logs are stored in the %SystemRoot%\System32\Config folder. If you turn on this registry value, a full log file is automatically backed up in the %SystemRoot%\System32\Config folder, the log file is cleared, and event logging resumes.
If you turn on this registry value, you must make sure to move or delete the backup log files from the System volume. If you do not, the volume may become full. Microsoft recommends that you implement a manual or automated procedure to move or delete the backup log files to prevent the backup log files from consuming all of the space on the System volume. If you turn on this registry value, take immediate action if you receive a "Disk full" message.
When a log file is successfully backed up, event 524 is logged with a source of "eventlog" in the Security event log file. The event is similar to:
The Security log file was saved as Security-2002-02-05-22-48-40-042.evt because the current log file is full.
The name of the backup file is a concatenation of the log file name and the date and time (in coordinated universal time, or UTC). The name has this format: