diff --git a/src/WixToolset.BuildTasks/DoIt.cs b/src/WixToolset.BuildTasks/DoIt.cs
index aeeb428..07bf05e 100644
--- a/src/WixToolset.BuildTasks/DoIt.cs
+++ b/src/WixToolset.BuildTasks/DoIt.cs
@@ -4,8 +4,6 @@ namespace WixToolset.BuildTasks
 {
     using System;
     using System.Collections.Generic;
-    using System.Linq;
-    using System.Reflection;
     using System.Runtime.InteropServices;
     using Microsoft.Build.Framework;
     using Microsoft.Build.Utilities;
@@ -111,9 +109,17 @@ public sealed class DoIt : Task
 
         public override bool Execute()
         {
+            var serviceProvider = new WixToolsetServiceProvider();
+
+            var listener = new MsbuildMessageListener(this.Log, "WIX", this.BuildEngine.ProjectFileOfTaskNode);
+
             try
             {
-                this.ExecuteCore();
+                this.ExecuteCore(serviceProvider, listener);
+            }
+            catch (WixException e)
+            {
+                listener.Write(e.Error);
             }
             catch (Exception e)
             {
@@ -128,10 +134,8 @@ public override bool Execute()
             return !this.Log.HasLoggedErrors;
         }
 
-        private void ExecuteCore()
+        private void ExecuteCore(IServiceProvider serviceProvider, IMessageListener listener)
         {
-            var listener = new MsbuildMessageListener(this.Log, "WIX", this.BuildEngine.ProjectFileOfTaskNode);
-
             var commandLineBuilder = new WixCommandLineBuilder();
 
             commandLineBuilder.AppendTextUnquoted("build");
@@ -164,8 +168,6 @@ private void ExecuteCore()
 
             this.Log.LogMessage(MessageImportance.Normal, "wix.exe " + commandLineString);
 
-            var serviceProvider = new WixToolsetServiceProvider();
-
             var messaging = serviceProvider.GetService<IMessaging>();
             messaging.SetListener(listener);
 
@@ -194,9 +196,9 @@ private IExtensionManager CreateExtensionManagerWithStandardBackends(IServicePro
                 {
                     extensionManager.Load(extension);
                 }
-                catch (ReflectionTypeLoadException e)
+                catch (WixException e)
                 {
-                    messaging.Write(ErrorMessages.InvalidExtension(extension, String.Join(Environment.NewLine, e.LoaderExceptions.Select(le => le.ToString()))));
+                    messaging.Write(e.Error);
                 }
             }
 
diff --git a/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj b/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
index 10a3f05..5020f89 100644
--- a/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
+++ b/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
@@ -32,7 +32,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="WixToolset.Core" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.Burn" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.WindowsInstaller" Version="4.0.*" />
   </ItemGroup>
diff --git a/src/WixToolset.Tools.Core/WixToolset.Tools.Core.csproj b/src/WixToolset.Tools.Core/WixToolset.Tools.Core.csproj
index 996258c..92111c6 100644
--- a/src/WixToolset.Tools.Core/WixToolset.Tools.Core.csproj
+++ b/src/WixToolset.Tools.Core/WixToolset.Tools.Core.csproj
@@ -11,8 +11,6 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="WixToolset.Data" Version="4.0.*" />
-    <PackageReference Include="WixToolset.Extensibility" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core" Version="4.0.*" />
   </ItemGroup>
 
diff --git a/src/wix/Program.cs b/src/wix/Program.cs
index 276eba5..a3251f8 100644
--- a/src/wix/Program.cs
+++ b/src/wix/Program.cs
@@ -3,8 +3,7 @@
 namespace WixToolset.Tools
 {
     using System;
-    using System.Linq;
-    using System.Reflection;
+    using System.Runtime.InteropServices;
     using WixToolset.Core;
     using WixToolset.Data;
     using WixToolset.Extensibility;
@@ -29,8 +28,28 @@ public static int Main(string[] args)
 
             var listener = new ConsoleMessageListener("WIX", "wix.exe");
 
-            var program = new Program();
-            return program.Run(serviceProvider, listener, args);
+            try
+            {
+                var program = new Program();
+                return program.Run(serviceProvider, listener, args);
+            }
+            catch (WixException e)
+            {
+                listener.Write(e.Error);
+
+                return e.Error.Id;
+            }
+            catch (Exception e)
+            {
+                listener.Write(ErrorMessages.UnexpectedException(e.Message, e.GetType().ToString(), e.StackTrace));
+
+                if (e is NullReferenceException || e is SEHException)
+                {
+                    throw;
+                }
+
+                return e.HResult;
+            }
         }
 
         /// <summary>
@@ -69,9 +88,9 @@ private static IExtensionManager CreateExtensionManagerWithStandardBackends(ISer
                 {
                     extensionManager.Load(extension);
                 }
-                catch (ReflectionTypeLoadException e)
+                catch (WixException e)
                 {
-                    messaging.Write(ErrorMessages.InvalidExtension(extension, String.Join(Environment.NewLine, e.LoaderExceptions.Select(le => le.ToString()))));
+                    messaging.Write(e.Error);
                 }
             }
 
diff --git a/src/wix/wix.csproj b/src/wix/wix.csproj
index a923c66..9cb5658 100644
--- a/src/wix/wix.csproj
+++ b/src/wix/wix.csproj
@@ -21,7 +21,6 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="WixToolset.Core" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.Burn" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.WindowsInstaller" Version="4.0.*" />
   </ItemGroup>