Could not load file or assembly System.Web.Mvc or

Question

currently working on asp.net mvc5 (old mvc3 project). It builds just fine, but when I start the project but when I run the project I am facing the following error.

Could not load file or assembly 'System.Web.Mvc' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

Not sure how I can can fix this, any ideas?

This is the Assembly Load Trace:

=== Pre-bind state information ===
LOG: DisplayName = System.Web.Mvc
 (Partial)
WRN: Partial binding information was supplied for an assembly:
WRN: Assembly Name: System.Web.Mvc | Domain ID: 2
WRN: A partial bind occurs when only part of the assembly display name is provided.
WRN: This might result in the binder loading an incorrect assembly.
WRN: It is recommended to provide a fully specified textual identity for the assembly,
WRN: that consists of the simple name, version, culture, and public key token.
WRN: See whitepaper http://go.microsoft.com/fwlink/?LinkId=109270 for more information and common solutions to this issue.
LOG: Appbase = file:///C:/Users/joaki/Source/Repos/2015-TimeAdministration/Source/V2/SalesWeb2/TimeReportV2/
LOG: Initial PrivatePath = C:\Users\joaki\Source\Repos\2015-TimeAdministration\Source\V2\SalesWeb2\TimeReportV2\bin
Calling assembly : (Unknown).
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Users\joaki\Source\Repos\2015-TimeAdministration\Source\V2\SalesWeb2\TimeReportV2\web.config
LOG: Using host configuration file: C:\Users\joaki\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Policy not being applied to reference at this time (private, custom, partial, or location-based assembly bind).
LOG: Attempting download of new URL file:///C:/Users/joaki/AppData/Local/Temp/Temporary ASP.NET Files/root/a90c5137/552c494a/System.Web.Mvc.DLL.
LOG: Attempting download of new URL file:///C:/Users/joaki/AppData/Local/Temp/Temporary ASP.NET Files/root/a90c5137/552c494a/System.Web.Mvc/System.Web.Mvc.DLL.
LOG: Attempting download of new URL file:///C:/Users/joaki/Source/Repos/2015-TimeAdministration/Source/V2/SalesWeb2/TimeReportV2/bin/System.Web.Mvc.DLL.
LOG: Using application configuration file: C:\Users\joaki\Source\Repos\2015-TimeAdministration\Source\V2\SalesWeb2\TimeReportV2\web.config
LOG: Using host configuration file: C:\Users\joaki\Documents\IISExpress\config\aspnet.config
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Redirect found in application configuration file: 4.0.0.1 redirected to 5.2.3.0.
LOG: Post-policy reference: System.Web.Mvc, Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35
LOG: Attempting download of new URL file:///C:/Users/joaki/AppData/Local/Temp/Temporary ASP.NET Files/root/a90c5137/552c494a/System.Web.Mvc.DLL.
LOG: Attempting download of new URL file:///C:/Users/joaki/AppData/Local/Temp/Temporary ASP.NET Files/root/a90c5137/552c494a/System.Web.Mvc/System.Web.Mvc.DLL.
LOG: Attempting download of new URL file:///C:/Users/joaki/Source/Repos/2015-TimeAdministration/Source/V2/SalesWeb2/TimeReportV2/bin/System.Web.Mvc.DLL.
WRN: Comparing the assembly name resulted in the mismatch: Major Version
ERR: Failed to complete setup of assembly (hr = 0x80131040). Probing terminated.

Web config:

    <?xml version="1.0" encoding="utf-8"?>
<!--
  For more information on how to configure your ASP.NET application, please visit
  http://go.microsoft.com/fwlink/?LinkId=301880
  -->
<configuration>
    <connectionStrings>
    <add name="SaleswebEntities" connectionString= ""/>
  </connectionStrings>

<appSettings>
    <add key="webpages:Version" value="3.0.0.0" />
    <add key="webpages:Enabled" value="false" />
    <add key="ClientValidationEnabled" value="true" />
    <add key="UnobtrusiveJavaScriptEnabled" value="true" />
  </appSettings>

  <system.web>
    <compilation debug="true" targetFramework="4.5.1" >
      <assemblies>
        <add assembly="System.Data.Entity, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"/>
      </assemblies>
    </compilation>

  <authentication mode="Forms">
    <forms loginUrl="~/Account/LogOn" timeout="2880" />
  </authentication>

  <membership>
    <providers>
      <clear />
      <add name="AspNetSqlMembershipProvider" type="System.Web.Security.SqlMembershipProvider" connectionStringName="ApplicationServices" enablePasswordRetrieval="false" enablePasswordReset="true" requiresQuestionAndAnswer="false" requiresUniqueEmail="false" maxInvalidPasswordAttempts="5" minRequiredPasswordLength="6" minRequiredNonalphanumericCharacters="0" passwordAttemptWindow="10" applicationName="/" />
    </providers>
  </membership>

  <profile>
    <providers>
      <clear />
      <add name="AspNetSqlProfileProvider" type="System.Web.Profile.SqlProfileProvider" connectionStringName="ApplicationServices" applicationName="/" />
    </providers>
  </profile>

  <roleManager enabled="false">
    <providers>
      <clear />
      <add name="AspNetSqlRoleProvider" type="System.Web.Security.SqlRoleProvider" connectionStringName="ApplicationServices" applicationName="/" />
      <add name="AspNetWindowsTokenRoleProvider" type="System.Web.Security.WindowsTokenRoleProvider" applicationName="/" />
    </providers>
  </roleManager>

  <pages>
    <namespaces>
      <add namespace="System.Web.Mvc" />
      <add namespace="System.Web.Mvc.Ajax" />
      <add namespace="System.Web.Mvc.Html" />
      <add namespace="System.Web.Routing" />
      <add namespace="System.Web.Helpers" />
      <add namespace="System.Web.WebPages" />
    </namespaces>
  </pages>
  </system.web>

  <system.webServer>
    <validation validateIntegratedModeConfiguration="false" />
    <modules runAllManagedModulesForAllRequests="true" />
  </system.webServer>

  <runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
      <dependentAssembly>
        <assemblyIdentity name="Newtonsoft.Json" culture="neutral" publicKeyToken="30ad4fe6b2a6aeed" />
        <bindingRedirect oldVersion="0.0.0.0-7.0.0.0" newVersion="7.0.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="System.Web.Optimization" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-1.1.0.0" newVersion="1.1.0.0" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="WebGrease" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="0.0.0.0-1.6.5135.21930" newVersion="1.6.5135.21930" />
      </dependentAssembly>
      <dependentAssembly>
        <assemblyIdentity name="Antlr3.Runtime" publicKeyToken="eb42632606e9261f" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-3.5.0.2" newVersion="3.5.0.2" />
      </dependentAssembly>
      <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.WebPages" 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="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
      </dependentAssembly>
    </assemblyBinding>
  </runtime>

</configuration>

Answer 1

If you carefully read the fusion log you posted, it gives you the information you need. I'll strip it down to the important lines.

LOG: Attempting download of new URL file:///C:/Users/joaki/Source/Repos/2015-TimeAdministration/Source/V2/SalesWeb2/TimeReportV2/bin/System.Web.Mvc.DLL.

The app is looking for System.Web.Mvc.dll. It's resolved it to the one under your web app's bin folder: C:\Users\joaki\Source\Repos\2015-TimeAdministration\Source\V2\SalesWeb2\TimeReportV2\bin\System.Web.Mvc.DLL

Next, it checks to see if there is any assembly binding redirect for that DLL in your web.config, and finds one:

LOG: Using application configuration file: C:\Users\joaki\Source\Repos\2015-TimeAdministration\Source\V2\SalesWeb2\TimeReportV2\web.config
LOG: Redirect found in application configuration file: 4.0.0.1 redirected to 5.2.3.0.
LOG: Post-policy reference: System.Web.Mvc, Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35

If you look in your web.config, there will be something like this:

  <dependentAssembly>
    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
    <bindingRedirect oldVersion="1.0.0.0-5.2.3.0" newVersion="5.2.3.0" />
  </dependentAssembly>

It then checks that the System.Web.Mvc.dll it's found in your app's bin directory is the same version:

WRN: Comparing the assembly name resulted in the mismatch: Major Version
ERR: Failed to complete setup of assembly (hr = 0x80131040). Probing terminated.

It complains that the Major Version mismatches. This is the first number in the 4-number version. If you go back in the log, that's because the System.Web.Mvc.dll in your bin folder is actually version 4.0.0.1, not the desired 5.2.3.0:

LOG: Redirect found in application configuration file: 4.0.0.1 redirected to 5.2.3.0.

You need to check your solution to make sure all projects that reference System.Web.Mvc are looking for the same, latest version. If you look at the Warnings in the Error List, you'll likely find warnings about version mismatches for this assembly.

Updating References

One solution is to right click on the Solution in Visual Studio, choose "Manage NuGet Packages for Solution..." and try to update the projects to use the same version of System.Web.Mvc.

It will also help if you clear out your bin folders beforehand.

You can also use the Package Manager Console instead to update the package across your solution:

Update-Package Microsoft.AspNet.Mvc -version 5.2.3.0

Answer 2

I'm not really sure if this will help. But I also had this message:

Could not load file or assembly 'System.Web.Mvc (1)' or one of its dependencies ...

I don't really know why but when I check out the bin folder of the web application, some of the DLL files have duplicates like "System.Web.Mvc(1).dll" and so on.

What I did was, I deleted all the duplicate files (file names with '(1)' or '(2)' ... on it), then rebuild the web app then it worked again.

Answer 3

Could you post your web.config file here?. It seems that you opened a mvc3 project in a newer environment and the migrating function of your IDE (i.e. Visual Studio) doesn't work well. The versions of System.Web.Mvc.DLL are mismatched (in config file and the one in bin/ directory). There are two ways to solve this: 1. Modify the version of System.Web.Mvc package/assembly in the config file. 2. Copy System.Web.Mvc.dll from your old project to the new project (bin/ folder).

I had faced the similar issue for other .dll files before. At that time, I chose to delete all .dll files and use NuGet Package Manager to download them again.