Could not load file or assembly 'System.Collections.Immutable' after upgrading ASP.NET to 1.1

[andriysavin]

I've upgraded to ASP.NET Core 1.1 (packages, SDK, VS ASP.NET tools), and now I'm getting the following exception when processing a page:

System.IO.FileLoadException: Could not load file or assembly 'System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'System.Collections.Immutable, Version=1.2.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' ---> System.IO.FileLoadException: Could not load file or assembly 'System.Collections.Immutable, Version=1.1.37.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)
File name: 'System.Collections.Immutable, Version=1.1.37.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

Some stack trace:

at Microsoft.AspNetCore.Mvc.Razor.Internal.RazorReferenceManager..ctor(ApplicationPartManager partManager, IOptions`1 optionsAccessor)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitTransient(TransientCallSite transientCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitTransient(TransientCallSite transientCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitTransient(TransientCallSite transientCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitClosedIEnumerable(ClosedIEnumerableCallSite closedIEnumerableCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitTransient(TransientCallSite transientCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped(ScopedCallSite scopedCallSite, ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProvider.<>c__DisplayClass16_0.b__0(ServiceProvider provider)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)
at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)
at Microsoft.AspNetCore.Mvc.ViewResult.d__26.MoveNext()

The runtime used is full .Net Framework. Here is the dependencies list:

 "dependencies": {
    "Microsoft.AspNetCore.Authentication.Cookies": "1.1.0",
    "Microsoft.AspNetCore.Authentication.OpenIdConnect": "1.1.0",
    "Microsoft.AspNetCore.Diagnostics": "1.1.0",
    "Microsoft.AspNetCore.Mvc": "1.1.0",
    "Microsoft.AspNetCore.Razor.Tools": {
      "version": "1.0.0-preview2-final",
      "type": "build"
    },
    "Microsoft.AspNetCore.Routing": "1.1.0",
    "Microsoft.AspNetCore.Server.IISIntegration": "1.1.0",
    "Microsoft.AspNetCore.Server.Kestrel": "1.1.0",
    "Microsoft.AspNetCore.StaticFiles": "1.1.0",
    "Microsoft.Azure.ActiveDirectory.GraphClient": "2.1.1",
    "Microsoft.Azure.Search": "1.1.3",
    "Microsoft.Extensions.Configuration.EnvironmentVariables": "1.1.0",
    "Microsoft.Extensions.Configuration.Json": "1.1.0",
    "Microsoft.Extensions.Configuration.UserSecrets": "1.1.0",
    "Microsoft.Extensions.Logging": "1.1.0",
    "Microsoft.Extensions.Logging.Console": "1.1.0",
    "Microsoft.Extensions.Logging.Debug": "1.1.0",
    "Microsoft.Extensions.Options.ConfigurationExtensions": "1.1.0",
    "Microsoft.VisualStudio.Web.BrowserLink.Loader": "14.1.0",
     <Non-MS project packages>
  }

[RemyBoyer]

I just cleaned the bin/ folders then this error disappeared.

[andriysavin]

@RemyBoyer In my case that wasn't enough. I had to delete 'System.Collections.Immutable' package of version 1.1.37.0 from the NuGet cache to make all working. That means I'm not sure if this issue won't reappear if the package of that version gets in the cache again.

[Eilon]

@pranavkm @ericstj any ideas on this?

[pranavkm]

Most likely a bad app.config. Deleting the bin directory should work. I'm not entirely sure why "Clean" doesn't help here though.' Similar issue here - dotnet/aspnetcore#1826

[andriysavin]

@pranavkm I don't have app.config.

[pranavkm]

The CLI typically produces an app.config for projects targeting desktop (net4x). These don't seem to get removed as part of clean and are usually the cause of these sort of issues. Perhaps forcing the restore (by removing the package from the global install directory) caused it to rebuild the config which fixed the issue. I'm not entirely sure why the file in the .nuget directory would be incorrect. You could try wiping all your nuget caches (http://docs.nuget.org/ndocs/tools/nuget.exe-cli-reference#locals) to be certain this isn't caused by bad caching.

[andriysavin]

@pranavkm If you're talking about an autogenerated app.config (which is produced in the bin folder and is not present in the project tree), then you're right, I have one. Here's what it has after the cleanups I did:

<dependentAssembly>
        <assemblyIdentity name="System.Collections.Immutable" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
        <bindingRedirect oldVersion="1.1.37.0" newVersion="1.2.1.0" />
        <bindingRedirect oldVersion="1.2.0.0" newVersion="1.2.1.0" />
      </dependentAssembly>

[andriysavin]

As I managed to get it working and we have an explanation of a possible cause, I'm closing this issue, thanks to everyone 👍

[marchy]

We are experiencing this issue on Azure.
How do you force Azure to clear the Nuget cache?

[Hecatron]

I was having a similar problem, I initially tried flushing the nuget cache with

nuget locals all -clear

But this didn't seem to solve anything
then I deleted the contents of the bin directory and this seemed to sort things out

[cshaa]

This is for all the people that get the “could not load assembly” error and no solution works for them – have you installed the System.Collections.Immutable NuGet package? I've been Googling for hours only to realize that Intellisense is not clever enough to install a NuGet package, instead it only referenced a “referential” package which contains the API but cannot be used in practise.

Sorry for spamming the repo but there aren't more relevant results on Google.