Bundled css link gets a 404 error

I am trying to get bundling to work in ASP.NET MVC 4. I am getting a 404 error from the link generated for the bundled CSS. I have done the following:

1. Installed the "Microsoft ASP.NET Web Optimization Framework" package via NuGet (v4.0.20710.0)

2. Created a BundleConfig class in the App_Start dir with the following contents:

using System.Web.Optimization;
namespace BsdAppTemplate.Web_Nancy.App_Start
{
public class BundleConfig
{
public static void RegisterBundles(BundleCollection bundles)
{
bundles.Add(new StyleBundle("~/bundles/styles/cvi").Include(
"~/mainstyles.css"
));
}
}
}

3. Added the following to Web.config at site root:

<system.web>
<compilation debug="false" targetFramework="4.5" />

<pages>
<namespaces>
<add namespace="System.Web.Optimization"/>
...
</namespaces>
</pages>
</system.web>


4. Added the following to the head element of my MVC layout file:

@Styles.Render("~/bundles/styles/cvi")

5. Copied the CSS file referenced in BundleConfig ("mainstyles.css") into the root directory of my web project.

When I view the source of a rendered file, I can see the link appears as:

<link href="/bundles/styles/cvi" rel="stylesheet"/>

This link results in a 404 when browsing to it, or viewing the page request in Chrome's network tab.

I have also tried the equivalent on a web form, but I get the same result (404) from the link generated when I add:

<%: Styles.Render("~/bundles/styles/cvi") %>

It seems that you have missed the step in which you apply your configuration by calling `RegisterBundles` in `Application_Start`:

protected void Application_Start()
{
...
BundleConfig.RegisterBundles(BundleTable.Bundles);
...
}

Usually in cases where the `BundleConfig` class is already there (either as a part of the project template or created by NuGet package during the installation) this call is also already present - this is why many tutorials are implicit about it.

You should also be aware that the `BundleConfig` class is there for separation of concerns and in order to keep the `Application_Start` clean. In simple cases nothing prevents you from registering bundles directly in `Application_Start`:

protected void Application_Start()
{
...
BundleTable.Bundles.Add(new StyleBundle("~/bundles/styles/cvi").Include("~/mainstyles.css"));

...
}

I had the same problem that my script bundle suddenly responded with 404. I a solution similar to @fiat answer that I found on [this blogpost][1].

The solution was to remove and add the `BundleModule` in the modules part section of the `system.webServer` section.

<modules runAllManagedModulesForAllRequests="true">
<remove name="BundleModule" />
<add name="BundleModule" type="System.Web.Optimization.BundleModule" />
</modules>

[1]:

[To see links please register here]

Found this question via google results, but the problem in my case was Windows 2008 needed this in `web.config` to work when compilation debug=false.

<system.webServer>
<modules>
<add name="BundleModule" type="System.Web.Optimization.BundleModule" />
</modules>
</system.webServer>

It worked fine on Win7 dev machine without this.

I hade same problem (in ASP.Net webform), i resolved my issue with Ignore "bundles/" route in Global.asax :

routeCollection.Ignore("bundles/{*catch}");

All my bundles names starting with "~/bundles/..." were not found in my WebAPI.
Adding the line to my RouteConfig.cs class

routeCollection.Ignore("bundles/{*catch}");

fixed my issue.

If you have this error while using Umbraco don't forget to add also this line to your web.config:

<add key="Umbraco.Core.ReservedUrls" value="~/bundles/" />

Figured I'll share what happened to me, when working on my machine I was running with "debug=false" so each individual file was loaded but when pushing to stage/prod I got 404's from the `/bundles/styles`.

Turns out I has a rewrite rule that was forcing a trailing slash so a request to

`/bundles/styles` was redirected to `/bundle/styles/` which does not exist. Added a exception for the rewrite and now things works just fine.