System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to

[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to [B]System.Web.WebPages.Razor.Configuration.HostSection. Type A originates from 'System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_2.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll'. Type B originates from 'System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 'C:\Users\xxxx\AppData\Local\Temp\Temporary ASP.NET Files\root\fe4980a2\10ea1996\assembly\dl3\33a3ac9e\f6af08a0_f8d6ce01\System.Web.WebPages.Razor.dll'.

This happen today when I use Nuget upgrade my MVC 4 asp.net 4.5 to last version on 1 November 2013 but can't get my project run normally after upgrade.

Normally look like I got System.Web.Razor version 3.0.0.0 but my web still use version 2.0.0.0 so I try to fix this

first change in root web.config by this

from

    <appSettings>

        <add key="webpages:Version" value="2.0.0.0" />

        <add key="webpages:Enabled" value="false" />

        <add key="PreserveLoginUrl" value="true" />

        <add key="ClientValidationEnabled" value="true" />

        <add key="UnobtrusiveJavaScriptEnabled" value="true" />

    </appSettings>

to

    <appSettings>

        <add key="webpages:Version" value="3.0.0.0" />

        <add key="webpages:Enabled" value="false" />

        <add key="PreserveLoginUrl" value="true" />

        <add key="ClientValidationEnabled" value="true" />

        <add key="UnobtrusiveJavaScriptEnabled" value="true" />

    </appSettings>

from

            <dependentAssembly>

                <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />

                <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

            </dependentAssembly>

            <dependentAssembly>

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

                <bindingRedirect oldVersion="1.0.0.0-4.0.0.0" newVersion="4.0.0.0" />

            </dependentAssembly>

            <dependentAssembly>

                <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />

                <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />

            </dependentAssembly>

to

            <dependentAssembly>

                <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />

                <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />

            </dependentAssembly>

            <dependentAssembly>

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

                <bindingRedirect oldVersion="1.0.0.0-5.0.0.0" newVersion="5.0.0.0" />

            </dependentAssembly>

            <dependentAssembly>

                <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />

                <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0" />

            </dependentAssembly>

change in web.config in ~/Views/

    <configSections>

        <sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">

            <section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />

            <section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />

        </sectionGroup>

    </configSections>

to

    <configSections>

        <sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">

            <section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />

            <section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" />

        </sectionGroup>

    </configSections>

from

        <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

to

        <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

from

        <pages

            validateRequest="false"

            pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"

            pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"

            userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">

            <controls>

                <add assembly="System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" />

            </controls>

        </pages>

to

        <pages

            validateRequest="false"

            pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"

            pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"

            userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">

            <controls>

                <add assembly="System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" />

            </controls>

        </pages>

now I can run my project with no problem (for now...)
Update...
yes i can build and run but intellisense not work anymore  look like i need Visual Studio 2003 for this job done.