You might see the following error in your event log for PeopleUpdate.
A critical application error occurred that could not be handled by the system. Please report the following information to your system administrator.
Error Information (Please report this to your System Administrator)
System.ApplicationException: Error deserializing configuration data from the file at C:\Program Files (x86)\WebActiveDirectory\PeopleUpdate\Configuration\WebADConfiguration.xml. at WAD.PeopleSearch.Config.SerializationHelper.GetApplicationConfigData() at WAD.PeopleSearch.Bus.ConfigurationManagerImplementation.GetConfigurationData() at WAD.PeopleSearch.Bus.ConfigurationManagerImplementation..ctor() at WAD.PeopleSearch.Bus.ConfigurationManagerImplementation.GetConfigurationManager() at WAD.PeopleSearch.Web.WadPage.OnInit(EventArgs e)
PeopleUpdate uses an XML file to store configuration data and sometimes it gets locked during a write sequence. If the error occurs repeatedly, you might start and stop the web site, recycle the application pool, or restart IIS to release the lock. The lock shouldn’t cause any problems reading from the file for normal operations but updates made to the PeopleUpdate configuration through the Admin Console might fail.