Forum Visual Studio

Can't compile project - VB.Net - Fatal error BC2000 - Xamarin/MonoDevelop

MirageMirage USMember

Hey All,

Just downloaded Xamarin/MonoDevelop in order to create a VB.Net based cross-platform application.

However Xamarin keeps returning a fatal error when attempting to compile a default template.


  1. File > New > Solution

  2. VBNet > Gtk# 2.0 Project

  3. Name solution

  4. Click Play (Debug)


Error Fatal error BC2000 : compiler initialization failed unexpectedly: Project already has a reference to assembly System. A second reference to 'C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.0\System.dll' cannot be added. (Fatal error BC2000 ) (test111)

The above occurs if I click Play, Build, Run/Start Without Debugging, and Run/Start With Debugging.

There is only one reference to System within the References folder in the Solution tree.

Any help would be greatly appreciated!



  • MirageMirage USMember

    The above does not occur with a C# Gtk# 2.0 project.

  • JasonAwbreyJasonAwbrey USInsider, University, Developer Group Leader mod

    VB.NET is not supported

  • MirageMirage USMember

    Then why is the option there in New > Solution?

  • mhutchmhutch USMember, Xamarin Team Xamurai

    VB.NET support is part of the open-source MonoDevelop project that Xamarin Studio is based on, but it's not a feature that's officially supported by Xamarin. It will probably be moved out to an optional add-in, which will be installable via the Add-in Manager.

    However, please file a bug to track this issue.

Sign In or Register to comment.