diff --git a/EmulatorPkg/Unix/Host/Host.h b/EmulatorPkg/Unix/Host/Host.h
index 9d6d36ee71..66c7c8df12 100644
--- a/EmulatorPkg/Unix/Host/Host.h
+++ b/EmulatorPkg/Unix/Host/Host.h
@@ -82,7 +82,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #undef NTOHS
 #undef HTONS
 #undef B0
-
+#undef CR3
 
 #include <PiPei.h>
 #include <Uefi.h>