Event ID 5173 — IIS WAS Configuration

Applies To: Windows Server 2008

The Internet Information Services (IIS) Windows Process Activation Service (WAS) configuration manager manages configuration for the application pools and protocol adapters that it maintains. If WAS encounters problems when it reads configuration or reacts to configuration change notifications, configuration changes for the entities it manages may not be processed.

Event Details

Product: Internet Information Services
ID: 5173
Source: Microsoft-Windows-WAS
Version: 7.0
Message: The Windows Process Activation Service encountered an error trying to read configuration data for config section '%1' from file '%2', line number '%3'. The error message is: '%4'. The data field contains the error number.


Correct a corrupted configuration file

If a configuration file such as ApplicationHost.config contains invalid characters, the Windows Process Activation Service (WAS) may be unable to read configuration data from the file.

Possible resolutions include:

  • Correct the invalid characters inside the file at the location indicated by the event log message.
  • Restore a recent copy of the configuration file from backup.

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

Correct invalid characters in the configuration file

To correct invalid characters in the configuration file:

  1. Using Windows Explorer, naviagate to the configuration file location. For ApplicationHost.config, the default location is %Windir%\system32\inetsrv\config.

  2. Using a text editor, open the file to the line number indicated by the event log message.

  3. Correct the invalid characters that you find.

    Note: An earlier version of the configuration file, if available, may serve as a useful comparison.

  4. Save and close the file.

  5. If corrections to the file do not resolve the issue, you can restore the configuration file from a backup if one is available. To do this, see the following procedure.

Restore a configuration file from backup

To restore a configuration file from backup:

  • If you have a known good copy of the configuration file available, you can replace the current file with the good copy by simply copying the good file into the configuration file location. For ApplicationHost.config, the default file location is %Windir%\system32\inetsrv\config.
  • If the affected file is ApplicationHost.config and you have the IIS 7.0 configuration history feature enabled, you can restore an automatically saved backup from the configuration history store. Earlier versions of the ApplicationHost.config file are saved by default in subfolders under the %SystemDrive%\inetpub\history folder.


If the Windows Process Activation Service (WAS) is configured correctly, IIS will serve pages successfully.

To confirm that WAS is executing successfully, perform the follow these steps:

  1. Open Internet Explorer.
  2. Browse to http://localhost or your Web site's default home page.
  3. Confirm that the expected page is displayed.
  4. Open the logs for the Web site and make sure 200 OK (request succeeded) is logged for the previous request. By default, Web site logs are located in the %SystemDrive%\inetpub\logs\LogFiles directory.

Note:  If logging is set to centralized, the log file size will grow over time. The minimum possible (and configurable) log file size is 1 MB.

IIS WAS Configuration

Internet Information Services (IIS) 7.0