Costura: An Unhandled Exception Occurred: Failed To Execute Weaver

This error occurs consistently in a medium-sized, multi-project VB.NET 4.5.2 VS 2017 solution. I have Costura (2.0.1 with Fody 3.0.3) working fine in a smaller C# project (with Obfusca obfuscation as well).

I installed Costura (using VS NuGet) into the two target projects. (And tried a reinstall after the two expected FodyWeavers.xml files failed to appear in the projects. I ended up creating them manually.)

Fody: An unhandled exception occurred:
Exception:
Failed to execute weaver E:\VS\Projects\ProjectName\ProjectName\packages\Costura.Fody.2.0.1\netclassicweaver\Costura.Fody.dll
Type:
System.Exception
StackTrace:
   at InnerWeaver.ExecuteWeavers()
   at InnerWeaver.Execute()
Source:
FodyIsolated
TargetSite:
Void ExecuteWeavers()
Could not find 'System.Void'.
Type:
Fody.WeavingException
StackTrace:
   at TypeCache.FindType(String typeName)
   at ModuleWeaver.FindMsCoreReferences()
   at ModuleWeaver.Execute()
   at InnerWeaver.ExecuteWeavers()
Source:
FodyHelpers
TargetSite:
Mono.Cecil.TypeDefinition FindType(System.String)

The two main projects are of different types and are in the solution together only because they share some common code; one is a class library/plug-in while the other is a Windows desktop app with similar functionality. The error is identical for each target project.

After the automatic/default “Copy Local” functionality failed, I tried setting individual assemblies for inclusion (which I’ve done in another project successfully, and prefer):

  <Costura>
    <IncludeAssemblies>
      Newtonsoft.Json
      ...
    </IncludeAssemblies>
  </Costura>

Same error. NOTE: I’m artificially just embedding a single assembly here; normally there would be several, including project assemblies such as Common, Api, etc.

I’ve hunted around the forums and Issues here to no avail.