The full error message:
System.TypeInitializationException: The type initializer for 'MonoDevelop.Projects.Formats.MSBuild.MSBuildProjectService' threw an exception. ---> System.TypeLoadException: Method 'Initialize' in type 'MonoDevelop.Projects.Formats.MSBuild.RemoteBuildEngine' from assembly 'MonoDevelop.Core, Version=2.6.0.0, Culture=neutral, PublicKeyToken=null' does not have an implementation.
at MonoDevelop.Projects.Formats.MSBuild.MSBuildProjectService..cctor()
--- End of inner exception stack trace --- at MonoDevelop.Projects.Formats.MSBuild.MSBuildProjectService.InitializeItemHandler(SolutionItem item) at MonoDevelop.Projects.Formats.MSBuild.MSBuildFileFormat.ConvertToFormat(Object obj) at MonoDevelop.Projects.SolutionEntityItem.InitializeItemHandler() at MonoDevelop.Projects.SolutionItem.get_ItemHandler() at MonoDevelop.Projects.SolutionItem.NotifyModified(String hint) at MonoDevelop.Projects.Project.set_StockIcon(IconId value) at MonoDevelop.Projects.DotNetProject..ctor(String languageName) at MonoDevelop.Projects.DotNetProject..ctor(String languageName, ProjectCreateInformation projectCreateInfo, XmlElement projectOptions) at MonoDevelop.MonoDroid.MonoDroidProject..ctor(String languageName, ProjectCreateInformation info, XmlElement projectOptions) at MonoDevelop.MonoDroid.MonoDroidProjectBinding.CreateProject(ProjectCreateInformation info, XmlElement projectOptions) at MonoDevelop.Projects.ProjectService.CreateProject(String type, ProjectCreateInformation info, XmlElement projectOptions) at MonoDevelop.Ide.Templates.ProjectDescriptor.CreateItem(ProjectCreateInformation projectCreateInformation, String defaultLanguage) at MonoDevelop.Ide.Templates.SolutionDescriptor.CreateEntry(ProjectCreateInformation projectCreateInformation, String defaultLanguage) at MonoDevelop.Ide.Templates.ProjectTemplate.CreateWorkspaceItem(ProjectCreateInformation cInfo) at MonoDevelop.Ide.Projects.NewProjectDialog.CreateProject()