Can't resolve “Could not load file or assembly 'System.Web.Mvc' or one of its dependencies” with documentation found

Question

I tried to deploy two ASP.NET web projects (a Facebook app and a bot) to the same Azure web site but, after I got them both deployed I received:

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)

I'm not sure what I can do other than start all over and merge the two projects into a single project (not desirable) to republish. So far I've:

1. Installed, via NuGet, Microsoft.AspNet.Mvc as suggested in other threads. Both projects have versions 5.2.3.0 on them
2. Ensured the Web.config files have 5.2.3.0 on them

Bot

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

App

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

3. Ensured property "Copy Local" is set to "True" on both projects for reference System.Web.Mvc

Here's the stack trace:

[FileLoadException: 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)]

[FileLoadException: Could not load file or assembly 'System.Web.Mvc, Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)] System.Reflection.RuntimeAssembly._nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +0
System.Reflection.RuntimeAssembly.nLoad(AssemblyName fileName, String codeBase, Evidence assemblySecurity, RuntimeAssembly locationHint, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +36
System.Reflection.RuntimeAssembly.InternalLoadAssemblyName(AssemblyName assemblyRef, Evidence assemblySecurity, RuntimeAssembly reqAssembly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean throwOnFileNotFound, Boolean forIntrospection, Boolean suppressSecurityChecks) +152
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean forIntrospection) +77
System.Reflection.RuntimeAssembly.InternalLoad(String assemblyString, Evidence assemblySecurity, StackCrawlMark& stackMark, Boolean forIntrospection) +21 System.Reflection.Assembly.Load(String assemblyString) +28
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +38

[ConfigurationErrorsException: Could not load file or assembly 'System.Web.Mvc, Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.Configuration.CompilationSection.LoadAssemblyHelper(String assemblyName, Boolean starDirective) +738
System.Web.Configuration.CompilationSection.LoadAllAssembliesFromAppDomainBinDirectory() +217 System.Web.Configuration.CompilationSection.LoadAssembly(AssemblyInfo ai) +130
System.Web.Compilation.BuildManager.GetReferencedAssemblies(CompilationSection compConfig) +170
System.Web.Compilation.BuildManager.GetPreStartInitMethodsFromReferencedAssemblies() +92 System.Web.Compilation.BuildManager.CallPreStartInitMethods(String preStartInitListPath, Boolean& isRefAssemblyLoaded) +290
System.Web.Compilation.BuildManager.ExecutePreAppStart() +157
System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException) +549

[HttpException (0x80004005): Could not load file or assembly 'System.Web.Mvc, Version=5.2.3.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)]
System.Web.HttpRuntime.FirstRequestInit(HttpContext context) [phone] System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +95 System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +254

Answer 1

Please try going to https://[YourSiteName].scm.azurewebsites.net/DebugConsole/?shell=powershell

And execute the following @ the PowerShell prompt:

[System.Diagnostics.FileVersionInfo]::GetVersionInfo("d:\home\site\wwwroot\bin\System.Web.Mvc.dll").FileVersion

This will tell you what version the .Mvc.dll is.

Note: your live site files are under \site\wwwroot\

Answer 2

I resolved to start my web projects from scratch and see if I could solve this error. I was able to find this other answer on how to deploy two projects to a single Azure web site. The idea is to create a virtual directory under the main web site and publish your web site to the root web site and, in my case the bot, to the virtual directory. So far it seems to hold!