diff --git a/EmulatorPkg/Win/Host/WinGopInput.c b/EmulatorPkg/Win/Host/WinGopInput.c
index 1c67a1cb40..22f12f1448 100644
--- a/EmulatorPkg/Win/Host/WinGopInput.c
+++ b/EmulatorPkg/Win/Host/WinGopInput.c
@@ -404,6 +404,10 @@ WinNtWndRegisterKeyNotify (
 
   Private = GRAPHICS_PRIVATE_DATA_FROM_THIS (GraphicsIo);
 
+  if (Private == NULL) {
+    return EFI_INVALID_PARAMETER;
+  }
+
   Private->MakeRegisterdKeyCallback    = MakeCallBack;
   Private->BreakRegisterdKeyCallback   = BreakCallBack;
   Private->RegisterdKeyCallbackContext = Context;
diff --git a/EmulatorPkg/Win/Host/WinGopScreen.c b/EmulatorPkg/Win/Host/WinGopScreen.c
index 661573d777..bcbd153cfd 100644
--- a/EmulatorPkg/Win/Host/WinGopScreen.c
+++ b/EmulatorPkg/Win/Host/WinGopScreen.c
@@ -808,6 +808,7 @@ WinNtGraphicsWindowOpen (
 
   GopPrivateCreateQ (Private, &Private->QueueForRead);
 
+  Private->Signature                          = GRAPHICS_PRIVATE_DATA_SIGNATURE;
   Private->GraphicsWindowIo.Size              = WinNtWndSize;
   Private->GraphicsWindowIo.CheckKey          = WinNtWndCheckKey;
   Private->GraphicsWindowIo.GetKey            = WinNtWndGetKey;