diff --git a/src/AudioIOBase.h b/src/AudioIOBase.h
index 8490ea4e2..2cbd95b8e 100644
--- a/src/AudioIOBase.h
+++ b/src/AudioIOBase.h
@@ -34,7 +34,9 @@ class AudioIOBase;
 class AudacityProject;
 class AudioIOListener;
 class BoundedEnvelope;
-class MeterPanelBase;
+// Windows build needs complete type for parameter of wxWeakRef
+// class MeterPanelBase;
+#include "widgets/MeterPanelBase.h"
 using PRCrossfadeData = std::vector< std::vector < float > >;
 
 #define BAD_STREAM_TIME (-DBL_MAX)
diff --git a/src/ProjectAudioIO.h b/src/ProjectAudioIO.h
index f125f71dd..1924d5a44 100644
--- a/src/ProjectAudioIO.h
+++ b/src/ProjectAudioIO.h
@@ -15,7 +15,10 @@ Paul Licameli split from AudacityProject.h
 #include <wx/weakref.h>
 
 class AudacityProject;
-class MeterPanelBase;
+
+// Windows build needs complete type for parameter of wxWeakRef
+// class MeterPanelBase;
+#include "widgets/MeterPanelBase.h"
 
 ///\ brief Holds per-project state needed for interaction with AudioIO,
 /// including the audio stream token and pointers to meters