Aspnetcore: The "ResolveBlazorRuntimeDependencies" task failed unexpectedly

[danroth27]

Repro steps:

1. Install .NET Core SDK 3.1.102
2. Install the latest internal dogfood build of VS 16.6 P1
3. Pin the SDK version to 3.1.102 using a global.json file
4. Install the latest Blazor WebAssembly template build
5. In VS, create a new Blazor WebAssembly app

Expected result: Template is created cleanly without warnings or errors

Actual result: The following error shows up in the Error List (even though the template builds and runs cleanly):

The "ResolveBlazorRuntimeDependencies" task failed unexpectedly.
System.IO.FileNotFoundException: Could not load file or assembly 'BlazorApp5.dll' or one of its dependencies. The system cannot find the file specified.
File name: 'BlazorApp5.dll' ---> System.IO.FileNotFoundException: The system cannot find the file specified. (Exception from HRESULT: 0x80070002)
   at System.Reflection.AssemblyName.nGetFileInformation(String s)
   at System.Reflection.AssemblyName.GetAssemblyName(String assemblyFile)
   at Microsoft.AspNetCore.Components.WebAssembly.Build.ResolveBlazorRuntimeDependencies.ResolveRuntimeDependenciesCore(String entryPoint, IEnumerable`1 applicationDependencies, IEnumerable`1 monoBclAssemblies)
   at Microsoft.AspNetCore.Components.WebAssembly.Build.ResolveBlazorRuntimeDependencies.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext()

Workaround: Close and reopen the solution.

[mkArtakMSFT]

Closing as can't reproduce this any more.

[spmoran-blazor]

This is still a thing.

[ImmutableVector]

I have had this happen on 2 machines now.

[ImmutableVector]

This has been a problem since the new template came out.

[danroth27]

@spmoran-blazor @ImmutableVector Have you confirmed that you are using SDK version 3.1.102 or later? Are you possibly using an older preview build of 3.1.200 that shipped with a VS preview? If you are, could you try updating to the latest 16.5 preview and see if that helps?

[ImmutableVector]

@danroth27 My sdk is good, and I was running 16.4.6.

After installing the Preview build I have confirmed this is working! I apologies if that was part of the steps to get everything up and running initially. And seriously, thanks for the quick feed back!

[jeanpoulin]

Got the same issue on March 27 and resolved it by updating my visual studio 2019 to the latest version.

[JasOcher]

Updating VS fixed this error, but the Blazor Server project is now throwing a 500.0 Module "AspNetCoreModule" could not be found error.