diff --git a/src/CryptoNoteCore/SwappedMap.h b/src/CryptoNoteCore/SwappedMap.h
index dd32945c..350f5d11 100644
--- a/src/CryptoNoteCore/SwappedMap.h
+++ b/src/CryptoNoteCore/SwappedMap.h
@@ -13,6 +13,7 @@
 #include <vector>
 #include <boost/archive/binary_oarchive.hpp>
 #include <boost/archive/binary_iarchive.hpp>
+#include <iostream>
 
 template<class Key, class T> class SwappedMap {
 private: