diff --git a/Adapter.cc b/Adapter.cc
index 7ec0cdb..2a96092 100644
--- a/Adapter.cc
+++ b/Adapter.cc
@@ -113,8 +113,11 @@ namespace pEp {
 
         void shutdown()
         {
-            if (_sync_thread)
+        	pEpLog("called");
+            if (_sync_thread) {
+            	pEpLog("sync_is_running - injecting null event");
                 _inject_sync_event(nullptr, nullptr);
+            }
         }
 
         bool is_sync_running()
@@ -123,4 +126,3 @@ namespace pEp {
         }
     }
 }
-
diff --git a/Adapter.hh b/Adapter.hh
index 51dc87c..5f1d5d2 100644
--- a/Adapter.hh
+++ b/Adapter.hh
@@ -7,6 +7,13 @@
 #include <string>
 #include <pEp/sync_api.h>
 
+// TODO: put into not yet existing libpEpAdapter_utils.h, to be across whole libpEpAdapter
+#ifdef NDEBUG
+    #define pEpLog(msg)  do{}while(0)
+#else
+    #include <iostream>
+    #define pEpLog(msg) do{std::cerr << __FILE__ << "::" << __FUNCTION__ << " - " << msg << '\n';} while(0)
+#endif
 
 namespace pEp {
 
diff --git a/Adapter.hxx b/Adapter.hxx
index 3fd4db6..73947dc 100644
--- a/Adapter.hxx
+++ b/Adapter.hxx
@@ -47,7 +47,9 @@ namespace pEp {
                 }
             }
 
+            pEpLog("sync protocol loop started");
             do_sync_protocol(session(), (void *)obj);
+            pEpLog("sync protocol loop ended");
             unregister_sync_callbacks(session());
 
             session(release);
@@ -88,4 +90,3 @@ namespace pEp {
         }
     }
 }
-
diff --git a/Makefile.conf b/Makefile.conf
index ad355c9..bb95499 100644
--- a/Makefile.conf
+++ b/Makefile.conf
@@ -3,27 +3,33 @@
 # This file may be used under the terms of the GNU General Public License version 3
 # see LICENSE.txt
 
-######### Header #########
 HERE:=$(dir $(lastword $(MAKEFILE_LIST)))
 
-######### General #########
-BUILD_FOR:=$(shell uname)
+
 PREFIX=$(HOME)
+CXXFLAGS=-std=c++11 
 
-######### C and C++ #########
-CXXFLAGS=-std=c++11
+# Build target
+BUILD_FOR:=$(shell uname)
 
-######### C++ #########
 ifeq ($(BUILD_FOR),Linux)
+    $(info Building for Linux)
     CXX=g++
+    CXXFLAGS+=-fdiagnostics-color=always -O0 $(ENGINE_INC) -fPIC
 else ifeq ($(BUILD_FOR),Darwin)
+    $(info Building for Darwin)
     CXX=clang
+    CXXFLAGS+=-fcolor-diagnostics -O0 $(ENGINE_INC)
 endif
 
-ifeq ($(BUILD_FOR),Linux)
-    CXXFLAGS+=-fdiagnostics-color=always -O0 -g $(ENGINE_INC) -fPIC
-else ifeq ($(BUILD_FOR),Darwin)
-    CXXFLAGS+=-fcolor-diagnostics -O0 -g $(ENGINE_INC)
+# Debug or Release build
+DEBUG=1
+ifeq ($(DEBUG),1)
+    $(info Debug build (set DEBUG=0 for release build))
+    CXXFLAGS+=-g
+else
+    $(info Release Build (set DEBUG=1 for debug build))
+    CXXFLAGS+=-DNDEBUG=1
 endif
 
 ######### Engine #########
@@ -33,7 +39,8 @@ ENGINE_INC_PATH=$(HOME)/include
 ######### Overrides #########
 -include $(HERE)/local.conf
 
-# Add Prefixes to paths, if not already explicitly set in local.conf(s)
+# Add -L Prefixes to LIB/INC paths,
+# if not already explicitly set in local.conf
 ifndef ENGINE_LIB
     ENGINE_LIB=-L$(ENGINE_LIB_PATH)
 endif