diff --git a/src/Main/Base/Project/Src/Project/MSBuildFileProject.cs b/src/Main/Base/Project/Src/Project/MSBuildFileProject.cs
index 6106927b22..a357dd47ca 100644
--- a/src/Main/Base/Project/Src/Project/MSBuildFileProject.cs
+++ b/src/Main/Base/Project/Src/Project/MSBuildFileProject.cs
@@ -2,9 +2,9 @@
 // This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
 
 using System;
+using System.IO;
 using System.Threading.Tasks;
-using ICSharpCode.Core;
-using ICSharpCode.SharpDevelop.Gui;
+using System.Xml;
 
 namespace ICSharpCode.SharpDevelop.Project
 {
@@ -13,8 +13,29 @@ namespace ICSharpCode.SharpDevelop.Project
 	/// </summary>
 	public class MSBuildFileProject : AbstractProject
 	{
+		SolutionFormatVersion minimumSolutionVersion = SolutionFormatVersion.VS2005;
+		
 		public MSBuildFileProject(ProjectLoadInformation information) : base(information)
 		{
+			try {
+				using (XmlReader r = XmlReader.Create(information.FileName, new XmlReaderSettings { IgnoreComments = true, XmlResolver = null })) {
+					if (r.Read() && r.MoveToContent() == XmlNodeType.Element) {
+						string toolsVersion = r.GetAttribute("ToolsVersion");
+						Version v;
+						if (Version.TryParse(toolsVersion, out v)) {
+							if (v >= new Version(4, 0)) {
+								minimumSolutionVersion = SolutionFormatVersion.VS2010; // use 4.0 Build Worker
+							}
+						}
+					}
+				}
+			} catch (XmlException) {
+			} catch (IOException) {
+			}
+		}
+		
+		public override SolutionFormatVersion MinimumSolutionVersion {
+			get { return minimumSolutionVersion; }
 		}
 		
 		public override Task<bool> BuildAsync(ProjectBuildOptions options, IBuildFeedbackSink feedbackSink, IProgressMonitor progressMonitor)
diff --git a/src/Main/ICSharpCode.SharpDevelop.BuildWorker35/ICSharpCode.SharpDevelop.BuildWorker35.csproj b/src/Main/ICSharpCode.SharpDevelop.BuildWorker35/ICSharpCode.SharpDevelop.BuildWorker35.csproj
index 0ff86fbd03..3dcd0e8da6 100644
--- a/src/Main/ICSharpCode.SharpDevelop.BuildWorker35/ICSharpCode.SharpDevelop.BuildWorker35.csproj
+++ b/src/Main/ICSharpCode.SharpDevelop.BuildWorker35/ICSharpCode.SharpDevelop.BuildWorker35.csproj
@@ -18,12 +18,11 @@
     <IntermediateOutputPath>obj\$(Configuration)\</IntermediateOutputPath>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Platform)' == 'AnyCPU' ">
-    <PlatformTarget>AnyCPU</PlatformTarget>
+    <PlatformTarget>x86</PlatformTarget>
     <RegisterForComInterop>False</RegisterForComInterop>
     <GenerateSerializationAssemblies>Auto</GenerateSerializationAssemblies>
     <BaseAddress>4194304</BaseAddress>
     <FileAlignment>4096</FileAlignment>
-    <Prefer32Bit>True</Prefer32Bit>
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)' == 'Debug' ">
     <DebugSymbols>true</DebugSymbols>
diff --git a/src/Tools/Tools.build b/src/Tools/Tools.build
index 08d8fa9a47..aa742c378b 100644
--- a/src/Tools/Tools.build
+++ b/src/Tools/Tools.build
@@ -1,4 +1,4 @@
-<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" DefaultTargets="Build">
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0" DefaultTargets="Build">
 	<PropertyGroup>
 		<LanguageResourcePath>..\..\data\resources\</LanguageResourcePath>
 	</PropertyGroup>