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Event ID 9012 — IIS Application Host History Configuration

  • Article

Applies To: Windows Server 2008 R2

The ApplicationHost Helper Service (AppHostSvc) maintains a history of Internet Information Services (IIS) configuration by saving the ApplicationHost.config file to separate configuration history subdirectories. If you make a mistake when you modify the ApplicationHost.config file, you can restore an earlier version of the file from a configuration history subdirectory by copying the earlier version into the %Windir%\system32\inetsrv\config directory. You can specify the frequency with which AppHostSvc checks for configuration changes, the path of the directory that contains the subdirectories, and how many subdirectories to keep.

By default, the Application Host Helper Service checks for changes in the ApplicationHost.config file every two minutes. If it detects that the configuration has changed, it creates a backup. The default location for the configuration history files is %SystemDrive%\inetpub\history. AppHostSvc creates one subdirectory under this directory for each configuration file backup. By default, the maximum number of history subdirectories is 10. If the number of configuration history subdirectories reaches the maximum specified, the oldest subdirectory is deleted.

AppHostSvc is a runtime-independent service that does not require the Windows Process Activation Service (WAS) or the World Wide Web Publishing Service (W3SVC) to operate. AppHostSvc does not depend on any other service and its startup type is Automatic. If the ApplicationHost Helper Service is stopped, the configuration history feature will not work.

Event Details

Product: Internet Information Services
ID: 9012
Source: Microsoft-Windows-IIS-APPHOSTSVC
Version: 7.5
Symbolic Name: APPHOSTSVC_HISTORY_INVALID_CONFIG_FILE_ERROR
Message: The Application Host Helper Service has detected that %1 file doesn't contain valid configuration. Config history backup feature has been disabled. It will be re-enabled automatically once the configuration file is fixed.

Resolve

Edit application host history configuration

To change the application host history settings, edit the configHistory section in the ApplicationHost.config file.

To perform this procedure, you must have membership in Administrators, or you must have been delegated the appropriate authority.

To edit the configHistory section in the ApplicationHost.config file:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

  2. Change to the directory %Windir%\system32\inetsrv.

  3. Type appcmd add backup backupName to back up the ApplicationHost.config file.

    A directory with the backup name that you specify will be created under the %Windir%\system32\inetsrv\backup directory. If you do not specify a name, appcmd will generate a directory name automatically using the current date and time.

  4. Change the directory to %Windir%\system32\inetsrv\config.

  5. Type notepad ApplicationHost.config.

  6. In notepad, search for the configHistory section under the system.applicationHost section.

  7. Use the article IIS 7.0: configHistory Element (IIS Settings Schema) as a reference to return the configHistory section settings to a well-known state.

  8. Save and close the ApplicationHost.config file.

Verify

To verify the configuration of the AppHostSvc configuration history backup feature, you can do the following:

  • Use notepad to examine the current configHistory section settings in the ApplicationHost.config file.
  • Use the Appcmd.exe command-line administration utility to view the configHistory section in the ApplicationHost.config file.

To perform these procedures, you must have membership in Administrators, or you must have been delegated the appropriate authority.

View the configHistory section by using notepad

To view the configHistory section by using notepad:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.

  2. Type cd %Windir%\system32\inetsrv\config.

  3. Type notepad ApplicationHost.config.

  4. In notepad, search for the configHistory section under system.applicationHost. The contents should resemble the following:

    <system.applicationHost>

        <configHistory enabled="true" path="%SystemDrive%\inetpub\history" maxHistories="10" period="00:02:00" />

    </system.applicationHost>

View the configHistory section by using Appcmd.exe

To view the configHistory section by using Appcmd.exe:

  1. Open an elevated Command Prompt window. Click Start, point to All Programs, click Accessories, right-click Command Prompt, and then click Run as administrator.
  2. Type cd %Windir%\system32\inetsrv.
  3. Type appcmd list config "Default Web Site" /section:configHistory /config:*. (This example uses the default Web site; replace the site name as necessary.)

See Also

IIS 7.0: configHistory Element (IIS Settings Schema)

IIS Application Host History Configuration

Internet Information Services (IIS) 7.5