diff --git a/src/com/opc/opcconnection.cpp b/src/com/opc/opcconnection.cpp
index 2fef4fb9f..c6db206e2 100644
--- a/src/com/opc/opcconnection.cpp
+++ b/src/com/opc/opcconnection.cpp
@@ -116,6 +116,10 @@ bool COpcConnection::ifInGroupList(const std::string& paGroupName){
 
 int COpcConnection::send_connect(const std::string& paGroupName, unsigned long paReqUpdateRate, float paDeadBand,
     forte::com_infra::CComLayer* paComCallback, std::vector<COpcProcessVar*> paNewItems){
+  if(mConnectionState == e_Disconnected){
+    mEventHandler->enableHandler();
+  }
+
   if(ifLetEventPass(e_Connect,paGroupName)){
     mConnectionState = e_Connecting;
     addGroup(paGroupName, paReqUpdateRate, paDeadBand, paComCallback);
diff --git a/src/com/opc/opceventhandler.cpp b/src/com/opc/opceventhandler.cpp
index b8b52df77..5b5cf69ca 100644
--- a/src/com/opc/opceventhandler.cpp
+++ b/src/com/opc/opceventhandler.cpp
@@ -29,25 +29,10 @@ bool COpcEventHandler::mIsSemaphoreEmpty = true;
 COpcEventHandler::TCallbackDescriptor COpcEventHandler::mCallbackDescCount = 0;
 
 COpcEventHandler::COpcEventHandler(CDeviceExecution& paDeviceExecution) : CExternalEventHandler(paDeviceExecution)  {
-  if (!isAlive()) {
-    this->start();
-    // Sleep to allow new thread to start
-    CThread::sleepThread(100);
-  }
 }
 
 COpcEventHandler::~COpcEventHandler(){
-  if (!mCommandQueue.isEmpty()) {
-    resumeSelfSuspend(); //wake-up and execute all commands in queue if exist
-  }
-
-  if (isAlive()) {
-    setAlive(false);
-    resumeSelfSuspend();
-    end();
-  }
-
-  clearCommandQueue(); //re-check and delete all commands in queue if still exist
+  clearCommandQueue(); //check and delete all commands in queue if not empty
 }
 
 void COpcEventHandler::clearCommandQueue(){
@@ -59,6 +44,22 @@ void COpcEventHandler::clearCommandQueue(){
       delete nextCommand;
     }
   }
+
+  for(TCallbackList::iterator itRunner = mComCallbacks.begin(); itRunner != mComCallbacks.end(); ++itRunner){
+    DEVLOG_ERROR("erase from command callback\n");
+    mComCallbacks.erase(itRunner);
+  }
+}
+
+void COpcEventHandler::executeCommandQueue(){
+  while(!mCommandQueue.isEmpty()) {
+    ICmd* nextCommand = getNextCommand();
+    if(nextCommand != nullptr) {
+      nextCommand->runCommand();
+      delete nextCommand;
+      nextCommand = nullptr;
+    }
+  }
 }
 
 void COpcEventHandler::sendCommand(ICmd *paCmd){
@@ -69,26 +70,14 @@ void COpcEventHandler::sendCommand(ICmd *paCmd){
 }
 
 void COpcEventHandler::run(){
-  HRESULT result = CoInitializeEx(nullptr, COINIT_MULTITHREADED);
-
-  if(result == S_OK){
-    while(isAlive()){
-      if (!isAlive()) {
-        break;
-      }
-      while(!mCommandQueue.isEmpty()) {
-        ICmd* nextCommand = getNextCommand();
-        if(nextCommand != nullptr) {
-          nextCommand->runCommand();
-          delete nextCommand;
-          nextCommand = nullptr;
-        }
-      }
-      selfSuspend();
+  while(isAlive()){
+    executeCommandQueue();
+    if (!isAlive()) {
+      break;
     }
+    selfSuspend();
   }
-
-  CoUninitialize();
+  executeCommandQueue(); // immediately try to clear the command queue after a stop
 }
 
 COpcEventHandler::TCallbackDescriptor COpcEventHandler::addComCallback(forte::com_infra::CComLayer* paComCallback){
diff --git a/src/com/opc/opceventhandler.h b/src/com/opc/opceventhandler.h
index 5f3261f71..ed10a7401 100644
--- a/src/com/opc/opceventhandler.h
+++ b/src/com/opc/opceventhandler.h
@@ -38,11 +38,31 @@ class COpcEventHandler : public CExternalEventHandler, private CThread{
 
     /* functions needed for the external event handler interface */
     void enableHandler() override {
-      //do nothing, start thread in the constructor
+      if (!isAlive()) {
+        start();
+        DEVLOG_INFO("COpcEventHandler: handler enabled\n");
+      }
     }
 
     void disableHandler() override {
-      //do nothing, end thread in the destructor
+      if (!mComCallbacks.empty()) {
+        DEVLOG_INFO("COpcEventHandler: command callback not empty\n");
+        resumeSelfSuspend();
+        return; // refuse, wait the second trigger
+      }
+
+      if (!mCommandQueue.isEmpty()) {
+        DEVLOG_INFO("COpcEventHandler: command queue not empty\n");
+        resumeSelfSuspend(); //wake-up, execute all commands in queue and continue
+      }
+
+      mStateSemaphore.timedWait(100000000); // wait 100ms to back wake-up
+      if (isAlive()) {
+        resumeSelfSuspend();
+        setAlive(false);
+        end();
+        DEVLOG_INFO("COpcEventHandler: handler disabled\n");
+      }
     }
 
     void setPriority(int) override {
@@ -65,6 +85,7 @@ class COpcEventHandler : public CExternalEventHandler, private CThread{
   private:
     ICmd* getNextCommand();
     void clearCommandQueue();
+    void executeCommandQueue();
 
     struct TComContainer{
         TCallbackDescriptor mCallbackDesc;