diff --git a/src/atcore.cpp b/src/atcore.cpp
index 3d47405..712de87 100644
--- a/src/atcore.cpp
+++ b/src/atcore.cpp
@@ -53,6 +53,7 @@ AtCore::AtCore(QObject *parent) :
     QObject(parent),
     d(new AtCorePrivate)
 {
+    qRegisterMetaType<PrinterState>("PrinterState");
     setState(DISCONNECTED);

     for (const auto &path : AtCoreDirectories::pluginDir) {
@@ -254,14 +255,17 @@ void AtCore::print(const QString &fileName)
     connect(printThread, &PrintThread::finished, thread, &QThread::quit);
     connect(printThread, &PrintThread::finished, printThread, &PrintThread::deleteLater);
     connect(thread, &QThread::finished, printThread, &PrintThread::deleteLater);
-    thread->start();
+    if(!thread->isRunning())
+        thread->start();
 }

 void AtCore::pushCommand(const QString &comm)
 {
     if (!pluginLoaded()) {
+        qDebug() << "Plugin not Loaded !";
         serial()->pushCommand(comm.toLocal8Bit());
     } else {
+        qDebug() << "Plugin Loaded !";
         serial()->pushCommand(plugin()->translate(comm));
     }
 }
diff --git a/src/plugins/repetierplugin.cpp b/src/plugins/repetierplugin.cpp
index b67ae97..3e93c82 100644
--- a/src/plugins/repetierplugin.cpp
+++ b/src/plugins/repetierplugin.cpp
@@ -60,9 +60,8 @@ void RepetierPlugin::validateCommand(const QString &lastMessage)
 {
     if (lastMessage.contains(_extruderTemp) || lastMessage.contains(_bedTemp)) {
         extractTemp(lastMessage);
-    } else if (lastMessage.contains(_ok) || lastMessage.contains(_wait)) {
-        emit readyForCommand();
     }
+    emit readyForCommand();
 }

 QByteArray RepetierPlugin::translate(const QString &command)
diff --git a/src/printThread.cpp b/src/printThread.cpp
index 324d724..f1736ed 100644
--- a/src/printThread.cpp
+++ b/src/printThread.cpp
@@ -3,6 +3,7 @@
 #include "gcodecommands.h"

 #include <QDebug>
+#include <QMutexLocker>

 class PrintThreadPrivate
 {
@@ -17,6 +18,7 @@ public:

 PrintThread::PrintThread(AtCore *parent, QString fileName) : d(new PrintThreadPrivate)
 {
+    QMutexLocker locker(&mutex1);
     d->core = parent;
     //QString cline;
     QFile file(fileName);
@@ -24,6 +26,7 @@ PrintThread::PrintThread(AtCore *parent, QString fileName) : d(new PrintThreadPr
     d->totalSize = file.bytesAvailable();
     d->stillSize = d->totalSize;
     d->gcodestream = new QTextStream(&file);
+    qDebug() << d->gcodestream->readLine();
 }

 void PrintThread::start()
@@ -38,6 +41,7 @@ void PrintThread::start()

 void PrintThread::commandReady()
 {
+    QMutexLocker locker(&mutex1);
     qDebug() << "Command Ready!";
     switch (d->core->state()) {
     case STARTPRINT:
@@ -45,9 +49,14 @@ void PrintThread::commandReady()
     case BUSY:
         d->core->setState(BUSY);
         nextLine();
+        while(d->cline.isEmpty())
+            nextLine();
+        qDebug() << "after nextline";
         if (!d->cline.isEmpty()) {
+            qDebug() << "cline not empty";
             d->core->pushCommand(d->cline);
         }
+        qDebug() << "busy break";
         break;

     case ERROR:
@@ -68,22 +77,36 @@ void PrintThread::commandReady()
         qDebug() << tr("Unknown State");
         break;
     }
+
     if (d->gcodestream->atEnd()) {
+        qDebug() << "atEnd";
         disconnect(d->core->plugin(), &IFirmware::readyForCommand, this, &PrintThread::commandReady);
         d->core->setState(FINISHEDPRINT);
         d->core->setState(IDLE);
         emit finished();
     }
+    else
+    {
+        qDebug() << "run it again";
+        commandReady();
+    }
 }

 void PrintThread::nextLine()
 {
-    d->cline = d->gcodestream->readLine();
+    qDebug() << "nextline";
+    QMutexLocker locker(&mutex2);
+    qDebug() << d->gcodestream;
+    QTextStream *gcodestream = d->gcodestream;
+    d->cline = gcodestream->readLine();
+    qDebug() << d->cline;
     d->stillSize -= d->cline.size() + 1; //remove read chars
+    qDebug() << d->stillSize;
     d->printProgress = float(d->totalSize - d->stillSize) * 100.0 / float(d->totalSize);
     emit(printProgressChanged(d->printProgress));
     d->cline = d->cline.simplified();
     if (d->cline.contains(QChar::fromLatin1(';'))) {
         d->cline.resize(d->cline.indexOf(QChar::fromLatin1(';')));
     }
+    qDebug() << "end nextline";
 }
diff --git a/src/printThread.h b/src/printThread.h
index 328122f..555e39e 100644
--- a/src/printThread.h
+++ b/src/printThread.h
@@ -20,6 +20,7 @@

 #include <QTextStream>
 #include <QFile>
+#include <QMutex>
 #include "atcore.h"

 class PrintThreadPrivate;
@@ -41,5 +42,7 @@ private slots:
     void commandReady();

 private:
+    mutable QMutex mutex1;
+    mutable QMutex mutex2;
     PrintThreadPrivate *d;
 };