ASP.NET Web API - PUT & DELETE Verbs Not Allowed - IIS 8

Change Your Web.Config file as below. It will act like charm.

In node <system.webServer> add below portion of code

<modules runAllManagedModulesForAllRequests="true">
  <remove name="WebDAVModule"/>
</modules>

After adding, your Web.Config will look like below

<system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules runAllManagedModulesForAllRequests="true">
        <remove name="WebDAVModule"/>
    </modules>
    <httpProtocol>
    <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Headers" value="Content-Type" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE, OPTIONS" />
    </customHeaders>
    </httpProtocol>
    <handlers>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" />
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" />
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0" />
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0" />
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
</system.webServer>

Okay. I finally got to the bottom of this. You need to jump through some hoops to get the PUT and DELETE verbs working correctly with IIS8. In fact if you install the release candidate of VS 2012 and create a new WEB API project you'll find that the sample PUT and DELETE methods return 404 errors out of the box.

To use the PUT and DELETE verbs with the Web API you need to edit %userprofile%\documents\iisexpress\config\applicationhost.config and add the verbs to the ExtensionlessUrl handler as follows:

Change this line:

<add name="ExtensionlessUrl-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

to:

<add name="ExtensionlessUrl-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

In addition to the above you should ensure WebDAV is not interfering with your requests. This can be done by commenting out the following lines from applicationhost.config.

<add name="WebDAVModule" image="%IIS_BIN%\webdav.dll" />
<add name="WebDAVModule" /> 
<add name="WebDAV" path="*" verb="PROPFIND,PROPPATCH,MKCOL,PUT,COPY,DELETE,MOVE,LOCK,UNLOCK" modules="WebDAVModule" resourceType="Unspecified" requireAccess="None" />

Also be aware that the default Web API convention is that your method name should be the same as the invoked HTTP verb. For example if you're sending an HTTP delete request your method, by default, should be named Delete.

Remove the WebDAV works perfectly for my case:

<modules>
  <remove name="WebDAVModule"/>
</modules>
<handlers>
  <remove name="WebDAV" />
  <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" 
       type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
</handlers>

it always better to solve the problem through the web.config instead of going to fix it through the iis or machine.config to grantee it wouldn't happen if the app hosted at another machine

Update your web.config

  <system.webServer>
    <modules>
      <remove name="WebDAVModule"/>
    </modules>
    <handlers>
      <remove name="WebDAV" />
      <remove name="ExtensionlessUrl-Integrated-4.0" />
      <add name="ExtensionlessUrl-Integrated-4.0"
           path="*."
           verb="GET,HEAD,POST,DEBUG,DELETE,PUT"
           type="System.Web.Handlers.TransferRequestHandler"
           preCondition="integratedMode,runtimeVersionv4.0" />
    </handlers>
  </system.webServer>

http://odetocode.com/blogs/scott/archive/2012/08/07/configuration-tips-for-asp-net-mvc-4-on-a-windows.aspx

Removes the need to modify your host configs.