So I brought up a new machine and tried to run my ASP.NET web site in IIS Express that uses Windows Authentication and was greeted with the following error: Error The requested page cannot be accessed because the related configuration data for the page is invalid. Details: This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault=“Deny”), or set explicitly by a location tag with overrideMode=“Deny” or the legacy allowOverride=“false”.