SharpDevelop Community

I'm working steadily through my 1.1 projects using SharpDevelop 2.1 to convert them to .NET 2.0. I'm on a fresh new computer and only have .NET 2.0 installed. I've managed to convert and build several projects smoothly but I'm getting an obscure error with two of them like this:

The default XML namespace of the project must be the MSBuild XML namespace. If the project is authored in the MSBuild 2003 format, please add xmlns="http://schemas.microsoft.com/developer/msbuild/2003" to the <Project> element. If the project has been authored in the old 1.0 or 1.2 format, please convert it to MSBuild 2003 format. (MSB4041)

I've googled and looked at the www.asp.net forums and there are certainly plenty of discussions about errors like this.  What I can't find in SharpDevelop is a way of "converting to MSBuild 2003 format". 

The relevant prjx file has this line at the beginning:

<Project name="DataAccessLayer_Instructors" standardNamespace="SumikinIntercom.Web.DataAccessLayer" description="" newfilesearch="None" enableviewstate="True" version="1.1" projecttype="C#">

Should I change the version number from 1.1 to 2.0 or add the schema reference to the Project element?

Judging from the discussions I've seen it's a bug in the .NET compiler (or something).

SharpDevelop 2.1 uses .sln (solution) and .csproj (project) files. The old .cmbx/.prjx cannot be used anymore. When opening a .cmbx, the .cmbx as well as the projects in it are converted.

I never tested "Add existing project" with .prjx files, maybe SharpDevelop adds a reference to the .prjx to the solution, which of course will cause an MSBuild error when compiling.

Remove the two projects from the solution and make add the converted .csproj files. If the projects are not yet converted, close the solution and open them individually - that should start the converter.