diff --git a/retroshare-gui/src/TorControl/SecureRNG.cpp b/retroshare-gui/src/TorControl/SecureRNG.cpp
index 3a6eacd83..60cf3c048 100644
--- a/retroshare-gui/src/TorControl/SecureRNG.cpp
+++ b/retroshare-gui/src/TorControl/SecureRNG.cpp
@@ -37,6 +37,7 @@
 #include <limits.h>
 
 #ifdef Q_OS_WIN
+#include <wtypes.h>
 #include <wincrypt.h>
 #endif