diff --git a/kcc.py b/kcc.py
index dec47c2..ca1efe6 100644
--- a/kcc.py
+++ b/kcc.py
@@ -27,7 +27,7 @@ import sys
 import os
 try:
     # noinspection PyUnresolvedReferences
-    from PyQt4 import QtGui
+    from PyQt4 import QtCore, QtGui, QtNetwork
 except ImportError:
     print "ERROR: PyQT4 is not installed!"
     exit(1)
@@ -41,13 +41,67 @@ elif sys.platform.startswith('linux'):
 else:
     from kcc import KCC_ui
 
+
+class QApplicationMessaging(QtGui.QApplication):
+    def __init__(self, argv):
+        QtGui.QApplication.__init__(self, argv)
+        self._memory = QtCore.QSharedMemory(self)
+        self._memory.setKey('KCC')
+        if self._memory.attach():
+            self._running = True
+        else:
+            self._running = False
+            if not self._memory.create(1):
+                raise RuntimeError(self._memory.errorString().toLocal8Bit().data())
+        self._key = 'KCC'
+        self._timeout = 1000
+        self._server = QtNetwork.QLocalServer(self)
+        if not self.isRunning():
+            self._server.newConnection.connect(self.handleMessage)
+            self._server.listen(self._key)
+
+    def isRunning(self):
+        return self._running
+
+    def handleMessage(self):
+        socket = self._server.nextPendingConnection()
+        if socket.waitForReadyRead(self._timeout):
+            self.emit(QtCore.SIGNAL('messageFromOtherInstance'), socket.readAll().data())
+
+    def sendMessage(self, message):
+        if self.isRunning():
+            socket = QtNetwork.QLocalSocket(self)
+            socket.connectToServer(self._key, QtCore.QIODevice.WriteOnly)
+            if not socket.waitForConnected(self._timeout):
+                return False
+            socket.write(message.encode('utf8'))
+            if not socket.waitForBytesWritten(self._timeout):
+                return False
+            socket.disconnectFromServer()
+            return True
+        return False
+
 freeze_support()
-APP = QtGui.QApplication(sys.argv)
+APP = QApplicationMessaging(sys.argv)
+if APP.isRunning():
+    if len(sys.argv) > 1:
+        APP.sendMessage('Araise!')
+        APP.sendMessage(sys.argv[1].decode(sys.getfilesystemencoding()))
+        sys.exit(0)
+    else:
+        messageBox = QtGui.QMessageBox()
+        icon = QtGui.QIcon()
+        icon.addPixmap(QtGui.QPixmap(':/Icon/icons/comic2ebook.png'), QtGui.QIcon.Normal, QtGui.QIcon.Off)
+        messageBox.setWindowIcon(icon)
+        QtGui.QMessageBox.critical(messageBox, 'KCC - Error', 'KCC is already running!', QtGui.QMessageBox.Ok)
+        sys.exit(1)
 KCC = QtGui.QMainWindow()
 UI = KCC_ui.Ui_KCC()
 UI.setupUi(KCC)
-GUI = KCC_gui.Ui_KCC(UI, KCC)
+GUI = KCC_gui.Ui_KCC(UI, KCC, APP)
 KCC.setWindowTitle("Kindle Comic Converter " + __version__)
 KCC.show()
 KCC.raise_()
+if len(sys.argv) > 1:
+    GUI.handleMessage(sys.argv[1].decode(sys.getfilesystemencoding()))
 sys.exit(APP.exec_())
diff --git a/kcc/KCC_gui.py b/kcc/KCC_gui.py
index ece60ba..3116656 100644
--- a/kcc/KCC_gui.py
+++ b/kcc/KCC_gui.py
@@ -317,7 +317,7 @@ class Ui_KCC(object):
             try:
                 str(dname)
             except Exception:
-                QtGui.QMessageBox.critical(MainWindow, 'KCC Error', "Path cannot contain non-ASCII characters.",
+                QtGui.QMessageBox.critical(MainWindow, 'KCC - Error', 'Path cannot contain non-ASCII characters.',
                                            QtGui.QMessageBox.Ok)
                 return
             if str(dname) != "":
@@ -349,7 +349,7 @@ class Ui_KCC(object):
             try:
                 str(fname)
             except Exception:
-                QtGui.QMessageBox.critical(MainWindow, 'KCC Error', "Path cannot contain non-ASCII characters.",
+                QtGui.QMessageBox.critical(MainWindow, 'KCC - Error', 'Path cannot contain non-ASCII characters.',
                                            QtGui.QMessageBox.Ok)
                 return
             if str(fname) != "":
@@ -577,7 +577,7 @@ class Ui_KCC(object):
         GUI.JobList.scrollToBottom()
 
     def showDialog(self, message):
-        QtGui.QMessageBox.critical(MainWindow, 'KCC Error', message, QtGui.QMessageBox.Ok)
+        QtGui.QMessageBox.critical(MainWindow, 'KCC - Error', message, QtGui.QMessageBox.Ok)
 
     def updateProgressbar(self, new=False, status=False):
         if new == "status":
@@ -643,7 +643,11 @@ class Ui_KCC(object):
                                                            'GammaSlider': float(self.GammaValue)*100}))
         self.settings.sync()
 
-    def __init__(self, UI, KCC):
+    def handleMessage(self, message):
+        #TODO
+        print message
+
+    def __init__(self, UI, KCC, APP):
         global GUI, MainWindow
         GUI = UI
         MainWindow = KCC
@@ -714,6 +718,7 @@ class Ui_KCC(object):
             self.addMessage('Cannot find <a href="http://www.7-zip.org/download.html">7za</a>!'
                             ' Processing of CB7/7Z files will be disabled.', 'warning')
 
+        APP.connect(APP, QtCore.SIGNAL('messageFromOtherInstance'), self.handleMessage)
         GUI.BasicModeButton.clicked.connect(self.modeBasic)
         GUI.AdvModeButton.clicked.connect(self.modeAdvanced)
         GUI.DirectoryButton.clicked.connect(self.selectDir)