Invalid / Missing Importer issue

Hello all,
I have a Invalid / Missing Importer issue, that seems to be frequent.
I’ve worked with XNA when it was still XNA and with the Content Pipeline. Everything I can find on this problem seems to want me to add Monogame.extended and I don’t want to! Although I plan to down the road a bit. I’m I missing anything in the code below? Thanks, Bubba

#pragma warning disable CS8603
using Microsoft.Xna.Framework;
using Microsoft.Xna.Framework.Graphics;
using Microsoft.Xna.Framework.Content;
using Microsoft.Xna.Framework.Content.Pipeline;
using Microsoft.Xna.Framework.Content.Pipeline.Serialization.Compiler;
namespace MGDevExt
{
public class MyObjExt
{
private string m_rawContent = string.Empty;
public string RawContent
{
get { return m_rawContent; }
set { m_rawContent = value; }
}

    public MyObjExt() { }
}

[ContentImporter(".myobj", DefaultProcessor = nameof(MyObjExtImporter), DisplayName = "MyObjExtProcessor")]
class MyObjExtImporter : ContentImporter<string>
{
    public override string Import(string filename, ContentImporterContext context)
    {
        context.Logger.LogMessage("Importing MyObjExt file: {0}", filename);
        //using (StreamReader sr =  new StreamReader(filename))
        //{
        //    return sr.ReadToEnd();
        //}
        return "test";
    }
}

[ContentProcessor(DisplayName = "MyObjExtProcessor")]
public class MyObjExtProcessor : ContentProcessor<string, MyObjExt>
{
    public MyObjExtProcessor() { }

    public override MyObjExt Process(string input, ContentProcessorContext context)
    {
        MyObjExt myObjExt = new MyObjExt();
        myObjExt.RawContent = input;
        return myObjExt;
    }
}

[ContentTypeWriter]
class MyObjExtWriter : ContentTypeWriter<MyObjExt>
{
    public override string GetRuntimeType(TargetPlatform targetPlatform)
    {
        return typeof(MyObjExt).AssemblyQualifiedName;
    }

    public override string GetRuntimeReader(TargetPlatform targetPlatform)
    {
        return typeof(MyObjExtReader).AssemblyQualifiedName;
    }

    protected override void Write(ContentWriter output, MyObjExt value)
    {
        output.Write(value.RawContent);
    }
}

class MyObjExtReader : ContentTypeReader<MyObjExt>
{
    protected override MyObjExt Read(ContentReader input, MyObjExt existingInstance)
    {
        MyObjExt myobjExt = new MyObjExt();
        string content = input.ReadString();
        myobjExt.RawContent = content;
        return myobjExt;
    }
}

}

Found the answer myself. When I installed the previous version of MonoGame I had to manually set the ‘OpenWith’ in the solution explorer because MonoGame and Visual Studio did not. It didn’t update it to the latest version of the MGCB Editor but the pipeline was updated. This was fine for built in content (textures, fbx etc) but not custom content. Once I read the hotfix listing at the top of the forum I went to the link and did some searches and found the answer that way.
Regards,
Bubba