Bug 12080 - Can't compile project - VB.Net - Fatal error BC2000 - Xamarin/MonoDevelop
Summary: Can't compile project - VB.Net - Fatal error BC2000 - Xamarin/MonoDevelop
Status: NEW
Alias: None
Product: Xamarin Studio
Classification: Desktop
Component: VB.Net Binding ()
Version: 4.0.3
Hardware: PC Windows
: --- normal
Target Milestone: master
Assignee: Bugzilla
Depends on:
Reported: 2013-05-02 16:34 UTC by cc
Modified: 2013-05-02 16:34 UTC (History)
1 user (show)

Is this bug a regression?: ---
Last known good build:

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Description cc 2013-05-02 16:34:10 UTC
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.

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

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


This issue is being caused by having Project > Active Runtime > Microsoft .Net selected.

When Project > Active Runtime > Mono 2.10.9 is selected the issue does not occur.