.net ms14-059 - Windows update caused MVC3 and MVC4 stop working

5 Answers

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

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

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" />

4.0 (kb2993928)

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?

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)


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.

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