Learned something about bundling the hard way. Deployed a website and now the styling is all wrong? Getting 404 on your bundles? Only getting this on Release “builds”? Maybe you made the same error as we did.

In debug mode the bundles are rendered as individual script / link tags, but in release mode this is optimized in one virtual link. Make sure the bundle is not pointing to an existing file and is linking to a file. Our solution used links without extension and that threw IIS off.

bundles.Add(
/* wrong: new ScriptBundle("~/bundles/kendo") */
/*                       missing extension ^  */
   new ScriptBundle("~/bundles/kendo.js")
      .Include("~/Scripts/kendo/kendo.web.*", 
               "~/Scripts/kendo/kendo.aspnetmvc.*")
);

References

• MVC4 – Bundling does not work when optimizations are set to true at stackoverflow
• Bundling and Minification tutorial at asp.net