Shdocvw.dll is part of Internet Explorer (IExplorer.exe) and performs the HTML parsing and rendering. Shdocvw.dll hosts the Mshtml.dll component, as well as any other Active Document component that can be loaded in place in the browser when the user navigates to a specific document type. This DLL exposes interfaces allow it to be hosted separately as an ActiveX control. Interop.SHDocVw.dll is the Interop assembly for the Microsoft WebBrowser control and is recompiled by Patrick A.R. Echterhoff . The file Interop.SHDocVw.dll, re-signed by Patrick A.R. Echterhoff , is an Interop assembly that has been intergated by a 3rd-party into a .Net application.