diff --git a/Documentation/Build.Docs.csproj b/Documentation/Build.Docs.csproj
index dfdea83c..4120c85e 100644
--- a/Documentation/Build.Docs.csproj
+++ b/Documentation/Build.Docs.csproj
@@ -1,5 +1,5 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="2.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup Condition="'$(Configuration)' == 'Documentation'">
     <OutputPath>.\Source</OutputPath>
   </PropertyGroup>
diff --git a/Installers/Nsis/Build.Installer.Nsis.csproj b/Installers/Nsis/Build.Installer.Nsis.csproj
index 24ad4c79..79241529 100644
--- a/Installers/Nsis/Build.Installer.Nsis.csproj
+++ b/Installers/Nsis/Build.Installer.Nsis.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="2.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup Condition="'$(Configuration)' == 'Documentation'">
     <OutputPath>.</OutputPath>
   </PropertyGroup>
diff --git a/OpenTK.sln b/OpenTK.sln
index d0a80668..d76a215e 100644
--- a/OpenTK.sln
+++ b/OpenTK.sln
@@ -12,10 +12,12 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Build.Installer.Nsis", "Ins
 	ProjectSection(ProjectDependencies) = postProject
 		{A37A7E14-0000-0000-0000-000000000000} = {A37A7E14-0000-0000-0000-000000000000}
 		{CCE26215-7591-4CC3-8E39-9A08F8BF35E2} = {CCE26215-7591-4CC3-8E39-9A08F8BF35E2}
+		{31D19132-0000-0000-0000-000000000000} = {31D19132-0000-0000-0000-000000000000}
 		{62C0DB35-0000-0000-0000-000000000000} = {62C0DB35-0000-0000-0000-000000000000}
 		{650C6F3D-33B5-4216-9536-956AB42C0624} = {650C6F3D-33B5-4216-9536-956AB42C0624}
 		{A625BE88-0000-0000-0000-000000000000} = {A625BE88-0000-0000-0000-000000000000}
 		{868E37B3-0000-0000-0000-000000000000} = {868E37B3-0000-0000-0000-000000000000}
+		{5FDFF4B6-0000-0000-0000-000000000000} = {5FDFF4B6-0000-0000-0000-000000000000}
 	EndProjectSection
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Build.Tasks", "Source\Build.Tasks\Build.Tasks.csproj", "{CCE26215-7591-4CC3-8E39-9A08F8BF35E2}"
diff --git a/Source/Build.Tasks/Build.Tasks.csproj b/Source/Build.Tasks/Build.Tasks.csproj
index 7af4ea6e..c68c391c 100644
--- a/Source/Build.Tasks/Build.Tasks.csproj
+++ b/Source/Build.Tasks/Build.Tasks.csproj
@@ -1,5 +1,5 @@
-<?xml version="1.0" encoding="utf-8"?>
-<Project ToolsVersion="2.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
diff --git a/Source/Compatibility/OpenTK.Compatibility.csproj b/Source/Compatibility/OpenTK.Compatibility.csproj
index b9ebced9..a05cebc5 100644
--- a/Source/Compatibility/OpenTK.Compatibility.csproj
+++ b/Source/Compatibility/OpenTK.Compatibility.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="2.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
   <PropertyGroup>
     <ProjectType>Local</ProjectType>
     <ProductVersion>8.0.50727</ProductVersion>
diff --git a/Source/Examples/OpenTK.Examples.csproj b/Source/Examples/OpenTK.Examples.csproj
index 1a0c52b6..b051524e 100644
--- a/Source/Examples/OpenTK.Examples.csproj
+++ b/Source/Examples/OpenTK.Examples.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="2.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
   <PropertyGroup>
     <ProjectType>Local</ProjectType>
     <ProductVersion>8.0.50727</ProductVersion>
diff --git a/Source/GLControl/OpenTK.GLControl.csproj b/Source/GLControl/OpenTK.GLControl.csproj
index 1deee620..65c17422 100644
--- a/Source/GLControl/OpenTK.GLControl.csproj
+++ b/Source/GLControl/OpenTK.GLControl.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="2.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
   <PropertyGroup>
     <ProjectType>Local</ProjectType>
     <ProductVersion>8.0.50727</ProductVersion>
diff --git a/Source/OpenTK/OpenTK.csproj b/Source/OpenTK/OpenTK.csproj
index 473db17d..d91b0c6d 100644
--- a/Source/OpenTK/OpenTK.csproj
+++ b/Source/OpenTK/OpenTK.csproj
@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="2.0">
+<Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="4.0">
   <PropertyGroup>
     <ProjectType>Local</ProjectType>
     <ProductVersion>8.0.50727</ProductVersion>