2 files changed, 2 insertions, 0 deletions

diff --git a/src/WixToolset.BuildTasks/WixBuild_InProc.cs b/src/WixToolset.BuildTasks/WixBuild_InProc.cs
index a45d2369..9cba0f62 100644
--- a/src/WixToolset.BuildTasks/WixBuild_InProc.cs
+++ b/src/WixToolset.BuildTasks/WixBuild_InProc.cs
@@ -3,6 +3,7 @@
 #if !NETCOREAPP
 namespace WixToolset.BuildTasks
 {
+    using System;
     using System.Threading;
     using System.Threading.Tasks;
     using WixToolset.Core.Burn;
diff --git a/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj b/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
index 6f43bae5..e4dfaf2f 100644
--- a/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
+++ b/src/WixToolset.BuildTasks/WixToolset.BuildTasks.csproj
@@ -19,6 +19,7 @@
 
   <ItemGroup Condition="'$(TargetFramework)'=='net461'">
     <PackageReference Include="Microsoft.Build.Tasks.Core" Version="14.3" />
+    <PackageReference Include="WixToolset.Core" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.Burn" Version="4.0.*" />
     <PackageReference Include="WixToolset.Core.WindowsInstaller" Version="4.0.*" />
   </ItemGroup>