diff --git a/Source/SpaceNav3D/SpaceNav3D.Build.cs b/Source/SpaceNav3D/SpaceNav3D.Build.cs
index 6ffbc64..ab6acc0 100644
--- a/Source/SpaceNav3D/SpaceNav3D.Build.cs
+++ b/Source/SpaceNav3D/SpaceNav3D.Build.cs
@@ -19,6 +19,8 @@ private string ThirdPartyPath
 
     public SpaceNav3D(ReadOnlyTargetRules Target) : base(Target)
 	{
+	PrivatePCHHeaderFile = "Private/SpaceNav3DPrivatePCH.h"; //UE4.21
+	
         // tanis - start faster compile time for small projects
         MinFilesUsingPrecompiledHeaderOverride = 1;
         bFasterWithoutUnity = true;