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.
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.
Correct invalid characters in the configuration file
To correct invalid characters in the configuration file:
Using Windows Explorer, naviagate to the configuration file location. For ApplicationHost.config, the default location is %Windir%\system32\inetsrv\config.
Using a text editor, open the file to the line number indicated by the event log message.
Correct the invalid characters that you find.
Note: An earlier version of the configuration file, if available, may serve as a useful comparison.
Save and close the file.
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 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.