diff --git a/libwhisper/WhisperPeer.cpp b/libwhisper/WhisperPeer.cpp
index 98bf0bc61..0951a3726 100644
--- a/libwhisper/WhisperPeer.cpp
+++ b/libwhisper/WhisperPeer.cpp
@@ -85,9 +85,10 @@ void WhisperPeer::sendMessages()
 	if (m_unseen.size())
 	{
 		RLPStream amalg;
-		unsigned msgCount = m_unseen.size();
+		unsigned msgCount;
 		{
 			Guard l(x_unseen);
+			msgCount = m_unseen.size();
 			while (m_unseen.size())
 			{
 				auto p = *m_unseen.begin();