diff --git a/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj b/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
index 6f92e88337..4f3f76c15e 100644
--- a/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
+++ b/tests/Avalonia.Markup.UnitTests/Avalonia.Markup.UnitTests.csproj
@@ -10,10 +10,11 @@
     <AppDesignerFolder>Properties</AppDesignerFolder>
     <RootNamespace>Avalonia.Markup.UnitTests</RootNamespace>
     <AssemblyName>Avalonia.Markup.UnitTests</AssemblyName>
-    <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>
+    <TargetFrameworkVersion>v4.5</TargetFrameworkVersion>
     <FileAlignment>512</FileAlignment>
     <NuGetPackageImportStamp>
     </NuGetPackageImportStamp>
+    <TargetFrameworkProfile />
   </PropertyGroup>
   <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
     <DebugSymbols>true</DebugSymbols>
@@ -34,7 +35,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="Microsoft.Reactive.Testing, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\Microsoft.Reactive.Testing.3.0.0\lib\net46\Microsoft.Reactive.Testing.dll</HintPath>
+      <HintPath>..\..\packages\Microsoft.Reactive.Testing.3.0.0\lib\net45\Microsoft.Reactive.Testing.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="Microsoft.VisualStudio.QualityTools.UnitTestFramework, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL" />
@@ -45,7 +46,7 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Reactive.Core, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\System.Reactive.Core.3.0.0\lib\net46\System.Reactive.Core.dll</HintPath>
+      <HintPath>..\..\packages\System.Reactive.Core.3.0.0\lib\net45\System.Reactive.Core.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Reactive.Interfaces, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
@@ -53,11 +54,15 @@
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Reactive.Linq, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\System.Reactive.Linq.3.0.0\lib\net46\System.Reactive.Linq.dll</HintPath>
+      <HintPath>..\..\packages\System.Reactive.Linq.3.0.0\lib\net45\System.Reactive.Linq.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Reactive.PlatformServices, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
-      <HintPath>..\..\packages\System.Reactive.PlatformServices.3.0.0\lib\net46\System.Reactive.PlatformServices.dll</HintPath>
+      <HintPath>..\..\packages\System.Reactive.PlatformServices.3.0.0\lib\net45\System.Reactive.PlatformServices.dll</HintPath>
+      <Private>True</Private>
+    </Reference>
+    <Reference Include="System.Reactive.Windows.Threading, Version=3.0.0.0, Culture=neutral, PublicKeyToken=94bc3704cddfc263, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\System.Reactive.Windows.Threading.3.0.0\lib\net45\System.Reactive.Windows.Threading.dll</HintPath>
       <Private>True</Private>
     </Reference>
     <Reference Include="System.Xml.Linq" />
@@ -66,6 +71,7 @@
     <Reference Include="System.Data" />
     <Reference Include="System.Net.Http" />
     <Reference Include="System.Xml" />
+    <Reference Include="WindowsBase" />
     <Reference Include="xunit.abstractions, Version=2.0.0.0, Culture=neutral, PublicKeyToken=8d05b1bb7a6fdb6c, processorArchitecture=MSIL">
       <HintPath>..\..\packages\xunit.abstractions.2.0.0\lib\net35\xunit.abstractions.dll</HintPath>
       <Private>True</Private>
diff --git a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
index 48b93107b1..3dcd8a4fbc 100644
--- a/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
+++ b/tests/Avalonia.Markup.UnitTests/Data/ExpressionObserverTests_Task.cs
@@ -95,7 +95,7 @@ namespace Avalonia.Markup.UnitTests.Data
         {
             using (var sync = UnitTestSynchronizationContext.Begin())
             {
-                var data = new { Foo = Task.FromException(new NotSupportedException()) };
+                var data = new { Foo = TaskFromException(new NotSupportedException()) };
                 var target = new ExpressionObserver(data, "Foo");
                 var result = new List<object>();
 
@@ -132,6 +132,13 @@ namespace Avalonia.Markup.UnitTests.Data
             }
         }
 
+        private Task TaskFromException(Exception e)
+        {
+            var tcs = new TaskCompletionSource<object>();
+            tcs.SetException(e);
+            return tcs.Task;
+        }
+
         private class Class1 : NotifyingBase
         {
             public Class1(Task<Class2> next)
diff --git a/tests/Avalonia.Markup.UnitTests/app.config b/tests/Avalonia.Markup.UnitTests/app.config
index fa66e8c206..654f911514 100644
--- a/tests/Avalonia.Markup.UnitTests/app.config
+++ b/tests/Avalonia.Markup.UnitTests/app.config
@@ -1,11 +1,11 @@
-<?xml version="1.0" encoding="utf-8"?>
+<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <runtime>
     <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
       <dependentAssembly>
-        <assemblyIdentity name="Moq" publicKeyToken="69f491c39445e920" culture="neutral" />
-        <bindingRedirect oldVersion="0.0.0.0-4.2.1510.2205" newVersion="4.2.1510.2205" />
+        <assemblyIdentity name="Moq" publicKeyToken="69f491c39445e920" culture="neutral"/>
+        <bindingRedirect oldVersion="0.0.0.0-4.2.1510.2205" newVersion="4.2.1510.2205"/>
       </dependentAssembly>
     </assemblyBinding>
   </runtime>
-</configuration>
\ No newline at end of file
+<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5"/></startup></configuration>
diff --git a/tests/Avalonia.Markup.UnitTests/packages.config b/tests/Avalonia.Markup.UnitTests/packages.config
index 34563ef392..ff66c030c1 100644
--- a/tests/Avalonia.Markup.UnitTests/packages.config
+++ b/tests/Avalonia.Markup.UnitTests/packages.config
@@ -1,11 +1,13 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="Microsoft.Reactive.Testing" version="3.0.0" targetFramework="net46" />
+  <package id="Microsoft.Reactive.Testing" version="3.0.0" targetFramework="net45" />
   <package id="Moq" version="4.2.1510.2205" targetFramework="net46" />
-  <package id="System.Reactive.Core" version="3.0.0" targetFramework="net46" />
-  <package id="System.Reactive.Interfaces" version="3.0.0" targetFramework="net46" />
-  <package id="System.Reactive.Linq" version="3.0.0" targetFramework="net46" />
-  <package id="System.Reactive.PlatformServices" version="3.0.0" targetFramework="net46" />
+  <package id="System.Reactive" version="3.0.0" targetFramework="net45" />
+  <package id="System.Reactive.Core" version="3.0.0" targetFramework="net45" />
+  <package id="System.Reactive.Interfaces" version="3.0.0" targetFramework="net45" />
+  <package id="System.Reactive.Linq" version="3.0.0" targetFramework="net45" />
+  <package id="System.Reactive.PlatformServices" version="3.0.0" targetFramework="net45" />
+  <package id="System.Reactive.Windows.Threading" version="3.0.0" targetFramework="net45" />
   <package id="xunit" version="2.1.0" targetFramework="net46" />
   <package id="xunit.abstractions" version="2.0.0" targetFramework="net46" />
   <package id="xunit.assert" version="2.1.0" targetFramework="net46" />