Windows update caused MVC3 and MVC4 stop working Mvc-4Windows Update

.Net Problem Overview

am i the only one who installed a Windows Update (8.1) on october 15, and suddenly MVC stop working because of this warning?

>Warning 1 Could not resolve this reference. Could not locate the assembly "System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL". Check to make sure the assembly exists on disk. If this reference is required by your code, you may get compilation errors.

It seems that this windows update installs a newer version of MVC with version number, and removes old version from program files folder.

Someone know how to fix this without crawling for each project?

.Net Solutions

Solution 1 - .Net

The best solution is update DLL to version Try use nuget:

Install-Package Microsoft.AspNet.Mvc -Version 4.0.40804 -Project <your project name>

This will automatically update


You just have to edit version System.Web.Mvc manually in:

<compilation debug="true" targetFramework="4.0">
    <add assembly="System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

Solution 2 - .Net

We had to manually touch each .csproj to update the version from to to get our builds going. Quite a pain.

New references should look like:

<Reference Include="System.Web.Mvc, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL" />

Solution 3 - .Net

Had the same issue after update:

> Security Update for Microsoft ASP.NET MVC 4.0 (KB2993928)

But only for project with a reference to the System.Web.Mvc, not installed by package.

My colleague, who hadn't installed Microsoft ASP.NET MVC 4.0 Runtime and didn't received the update, had no trouble and had still the reference to, not to

I manually changed the reference to, after check-in, my colleague could still build with a reference to
(Working both on Win7 Pro SP1, VS2013 Pro Update 3)

Solution 4 - .Net

Please see this blog, the recommended way is to update corresponding NuGet package:


To quote:

> The problem can be resolved by implemented one of the following > solutions: > > 1. (Preferred) Install Microsoft.AspNet.Mvc from the NuGet gallery (this will install a binding redirect in your web.config). You can do > this from the NuGet package manager or the NuGet console inside Visual > Studio: > > >Install-Package Microsoft.AspNet.Mvc -Version -Project PROJECTNAME > > MVC 4 version: 4.0.40804.0 > > MVC 3 version: 3.0.50813.1 > > 2. Manually update the reference to System.Web.MVC.dll (don’t use the one in the GAC). > > Try the Add Reference -> Assemblies -> Extensions dialog box.

Solution 5 - .Net

See this: Microsoft Asp.Net MVC Security Update MS14-059 broke my build! MS blogged about it since it obviously brought a lot of confusion

Solution 6 - .Net

For web project, you may have to update the configuration in the web.config as well:

    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35"/>
    <bindingRedirect oldVersion="" newVersion=""/>

Solution 7 - .Net

You need to change all the references to System.Web.Mvc within your solution. Just delete them and add the new version.

Also in the properties change copy local to true.

And in the web.config add the assambly binding to point to the new version of mvc:

		<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
				<assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" culture="neutral" />
				<bindingRedirect oldVersion="" newVersion="" />

Solution 8 - .Net


For me it was two simple steps:

First I changed all references to System.Web.Mvc from to,

Then I had to go to the properties of System.Web.Mvc (possibly because I had removed and re-added it) and change copy local to true.

Hope this is helpful for somebody.

Solution 9 - .Net

If you are still getting the same error after trying @Krzysztof solution or any of the other answers above, one work around that might work for you is to uninstall MVC Runtime 4.0


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Content TypeOriginal AuthorOriginal Content on Stackoverflow
QuestionYogurtuView Question on Stackoverflow
Solution 1 - .NetKrzysztof KalinowskiView Answer on Stackoverflow
Solution 2 - .NetZach La LondView Answer on Stackoverflow
Solution 3 - .NetJawsView Answer on Stackoverflow
Solution 4 - .NetMiguel LacoutureView Answer on Stackoverflow
Solution 5 - .Nete4rthdogView Answer on Stackoverflow
Solution 6 - .NetTHNView Answer on Stackoverflow
Solution 7 - .NetRobert BenyiView Answer on Stackoverflow
Solution 8 - .NetedencorbinView Answer on Stackoverflow
Solution 9 - .NetRicardo SanchezView Answer on Stackoverflow