scriptresource.axd 404 error in asp net 4 application - webresource works fine though

Looks like handlers needed to be added to system.webserver, per this blog: http://geekswithblogs.net/lorint/archive/2007/03/28/110161.aspx

<system.webServer>
  <handlers>
    <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" />
  </handlers>
</system.webServer>

Thanks for the assistance @Uwe Keim

I had the same issue today, but it was caused by a rewrite rule that was rewriting the request from /ScriptResource.axd' to/some_application/ScriptResource.axd', which wasn't a valid target. Correcting the rule to ignore urls with .axd resolved the issue.

This worked for me:

Add the below handler to your web.config:

<system.webServer>
<handlers>
<add name="ScriptResource" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" preCondition="integratedMode" />