diff --git a/server/Makefile b/server/Makefile
index f10e89c4..e0c148a9 100644
--- a/server/Makefile
+++ b/server/Makefile
@@ -31,11 +31,12 @@ else
 endif
 
 # Simplify building debuggable executables 'make DEBUG=-g STRIP=echo'
-DEBUG=-O3
+DEBUG=-O2
+SANITIZE=
+#-fsanitize=thread
 
-
-CXXFLAGS += $(ADD_CFLAGS) -std=c++14 -Wall -Wpedantic -Wno-unused-function $(DEBUG) -DHAS_FLAC -DHAS_OGG -DHAS_VORBIS -DHAS_VORBIS_ENC -DVERSION=\"$(VERSION)\" -I. -I.. -I../common
-LDFLAGS   = $(ADD_LDFLAGS) -lvorbis -lvorbisenc -logg -lFLAC 
+CXXFLAGS += $(ADD_CFLAGS) $(SANITIZE) -std=c++14 -Wall -Wpedantic -Wno-unused-function $(DEBUG) -DHAS_FLAC -DHAS_OGG -DHAS_VORBIS -DHAS_VORBIS_ENC -DVERSION=\"$(VERSION)\" -I. -I.. -I../common
+LDFLAGS   = $(ADD_LDFLAGS) $(SANITIZE) -lvorbis -lvorbisenc -logg -lFLAC 
 OBJ       = snapserver.o config.o control_server.o control_session_tcp.o control_session_http.o stream_server.o stream_session.o streamreader/streamUri.o streamreader/base64.o streamreader/streamManager.o streamreader/pcmStream.o streamreader/pipeStream.o streamreader/fileStream.o streamreader/processStream.o streamreader/airplayStream.o streamreader/spotifyStream.o streamreader/watchdog.o encoder/encoderFactory.o encoder/flacEncoder.o encoder/pcmEncoder.o encoder/oggEncoder.o ../common/sampleFormat.o
 
 ifneq (,$(TARGET))
diff --git a/server/control_server.cpp b/server/control_server.cpp
index f59c56f0..4a76fd32 100644
--- a/server/control_server.cpp
+++ b/server/control_server.cpp
@@ -47,23 +47,19 @@ ControlServer::~ControlServer()
 
 void ControlServer::cleanup()
 {
-    std::lock_guard<std::recursive_mutex> mlock(session_mutex_);
-    for (auto it = sessions_.begin(); it != sessions_.end();)
+    auto new_end = std::remove_if(sessions_.begin(), sessions_.end(), [](std::weak_ptr<ControlSession> session) { return session.expired(); });
+    auto count = distance(new_end, sessions_.end());
+    if (count > 0)
     {
-        if (it->expired())
-        {
-            SLOG(ERROR) << "Session inactive. Removing\n";
-            sessions_.erase(it++);
-        }
-        else
-            ++it;
+        SLOG(ERROR) << "Removing " << count << " inactive session(s), active sessions: " << sessions_.size() - count << "\n";
+        sessions_.erase(new_end, sessions_.end());
     }
 }
 
 
 void ControlServer::send(const std::string& message, const ControlSession* excludeSession)
 {
-    cleanup();
+    std::lock_guard<std::recursive_mutex> mlock(session_mutex_);
     for (auto s : sessions_)
     {
         if (auto session = s.lock())
@@ -72,6 +68,7 @@ void ControlServer::send(const std::string& message, const ControlSession* exclu
                 session->sendAsync(message);
         }
     }
+    cleanup();
 }
 
 
@@ -203,6 +200,7 @@ void ControlServer::stop()
     cancel_accept(acceptor_http_.first.get());
     cancel_accept(acceptor_http_.second.get());
     std::lock_guard<std::recursive_mutex> mlock(session_mutex_);
+    cleanup();
     for (auto s : sessions_)
     {
         if (auto session = s.lock())
diff --git a/server/snapserver.conf b/server/snapserver.conf
index 2258c64c..06aea0c1 100644
--- a/server/snapserver.conf
+++ b/server/snapserver.conf
@@ -12,7 +12,7 @@
 ###############################################################################
 
 # default values are commented
-# uncomment to change them
+# uncomment and edit to change them
 
 
 # HTTP RPC ####################################################################
diff --git a/server/stream_session.cpp b/server/stream_session.cpp
index 24149229..d34533d2 100644
--- a/server/stream_session.cpp
+++ b/server/stream_session.cpp
@@ -75,12 +75,15 @@ void StreamSession::stop()
     try
     {
         boost::system::error_code ec;
-        socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
-        if (ec)
-            LOG(ERROR) << "Error in socket shutdown: " << ec.message() << "\n";
-        socket_.close(ec);
-        if (ec)
-            LOG(ERROR) << "Error in socket close: " << ec.message() << "\n";
+        {
+            std::lock_guard<std::mutex> socketLock(socketMutex_);
+            socket_.shutdown(boost::asio::ip::tcp::socket::shutdown_both, ec);
+            if (ec)
+                LOG(ERROR) << "Error in socket shutdown: " << ec.message() << "\n";
+            socket_.close(ec);
+            if (ec)
+                LOG(ERROR) << "Error in socket close: " << ec.message() << "\n";
+        }
         if (readerThread_ && readerThread_->joinable())
         {
             LOG(DEBUG) << "StreamSession joining readerThread\n";
@@ -145,10 +148,12 @@ bool StreamSession::send(const msg::message_ptr& message)
 {
     // TODO on exception: set active = false
     //	LOG(INFO) << "send: " << message->type << ", size: " << message->getSize() << ", id: " << message->id << ", refers: " << message->refersTo << "\n";
-    std::lock_guard<std::mutex> activeLock(activeMutex_);
-    if (!active_)
-        return false;
-
+    std::lock_guard<std::mutex> socketLock(socketMutex_);
+    {
+        std::lock_guard<std::mutex> activeLock(activeMutex_);
+        if (!active_)
+            return false;
+    }
     boost::asio::streambuf streambuf;
     std::ostream stream(&streambuf);
     tv t;