 <p>Try changing the order of the handlers (remove then add). In this example I have removed all but the AJAX/script handler.</p> <pre><code>&lt;system.webServer&gt; &lt;modules runAllManagedModulesForAllRequests="true" /&gt; &lt;handlers&gt; &lt;remove name="WebServiceHandlerFactory-Integrated"/&gt; &lt;remove name="WebServiceHandlerFactory-ISAPI-2.0"/&gt; &lt;remove name="WebServiceHandlerFactory-ISAPI-2.0-64"/&gt; &lt;remove name="WebServiceHandlerFactory-ISAPI-4.0_32bit"/&gt; &lt;remove name="WebServiceHandlerFactory-ISAPI-4.0_64bit"/&gt; &lt;!--&lt;add name="WebServiceHandlerFactory-Integrated-4.0" ...&lt;/handlers&gt; </code></pre>