diff --git a/main.cpp b/main.cpp
index 4bf16f144..a28f1c686 100644
--- a/main.cpp
+++ b/main.cpp
@@ -2,6 +2,8 @@
 #include <QtGui/QApplication>
 #include "mainwindow.h"
 
+QSharedMemory mem_jt9("mem_jt9");
+
 int main(int argc, char *argv[])
 {
   QApplication a(argc, argv);
@@ -18,7 +20,20 @@ int main(int argc, char *argv[])
      a.setFont(font);
   }
 
-  MainWindow w;
+  // Create and initialize shared memory segment
+  if(!mem_jt9.attach()) {
+    if (!mem_jt9.create(sizeof(jt9com_))) {
+      QMessageBox::critical( 0, "Error", "Unable to create shared memory segment.");
+      exit(1);
+    }
+  }
+  char *to = (char*)mem_jt9.data();
+  int size=sizeof(jt9com_);
+  if(jt9com_.newdat==0) {
+  }
+  memset(to,0,size);         //Zero all decoding params in shared memory
+
+  MainWindow w(&mem_jt9);
   w.show();
   return a.exec();
 }
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 2b828188b..383e1f474 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -21,14 +21,13 @@ double dFreq[]={0.136,0.4742,1.838,3.578,5.357,7.078,10.130,14.078,
            18.104,21.078,24.918,28.078,50.293,70.091,144.489,432.178};
 
 WideGraph* g_pWideGraph = NULL;
-QSharedMemory mem_jt9("mem_jt9");
 
 QString rev="$Rev$";
 QString Program_Title_Version="  WSJT-X   v0.9, r" + rev.mid(6,4) +
                               "    by K1JT";
 
 //-------------------------------------------------- MainWindow constructor
-MainWindow::MainWindow(QWidget *parent) :
+MainWindow::MainWindow(QSharedMemory *shdmem, QWidget *parent) :
   QMainWindow(parent),
   ui(new Ui::MainWindow)
 {
@@ -193,6 +192,8 @@ MainWindow::MainWindow(QWidget *parent) :
                            QString::number(iret));
   }
 #endif
+  mem_jt9 = shdmem;
+  /*
   if(!mem_jt9.attach()) {
     if (!mem_jt9.create(sizeof(jt9com_))) {
       msgBox("Unable to create shared memory segment.");
@@ -203,6 +204,7 @@ MainWindow::MainWindow(QWidget *parent) :
   if(jt9com_.newdat==0) {
   }
   memset(to,0,size);         //Zero all decoding params in shared memory
+*/
 
   PaError paerr=Pa_Initialize();                    //Initialize Portaudio
   if(paerr!=paNoError) {
@@ -895,7 +897,7 @@ void MainWindow::OnExit()
 {
   g_pWideGraph->saveSettings();
   m_killAll=true;
-  mem_jt9.detach();
+  mem_jt9->detach();
   QFile quitFile(m_appDir + "/.quit");
   quitFile.open(QIODevice::ReadWrite);
   QFile lockFile(m_appDir + "/.lock");
@@ -1154,7 +1156,7 @@ void MainWindow::decode()                                       //decode()
   //newdat=1  ==> this is new data, must do the big FFT
   //nagain=1  ==> decode only at fQSO +/- Tol
 
-  char *to = (char*)mem_jt9.data();
+  char *to = (char*)mem_jt9->data();
   char *from = (char*) jt9com_.ss;
   int size=sizeof(jt9com_);
   if(jt9com_.newdat==0) {
@@ -1163,7 +1165,7 @@ void MainWindow::decode()                                       //decode()
     from += noffset;
     size -= noffset;
   }
-  memcpy(to, from, qMin(mem_jt9.size(), size));
+  memcpy(to, from, qMin(mem_jt9->size(), size));
 
   QFile lockFile(m_appDir + "/.lock");       // Allow jt9 to start
   lockFile.remove();
diff --git a/mainwindow.h b/mainwindow.h
index 443300a4e..03f20e3ce 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -21,7 +21,7 @@ class MainWindow : public QMainWindow
   Q_OBJECT
 
 public:
-  explicit MainWindow(QWidget *parent = 0);
+  explicit MainWindow(QSharedMemory *shdmem, QWidget *parent = 0);
   ~MainWindow();
 
 public slots:
@@ -309,6 +309,8 @@ private:
     SoundInThread soundInThread;             //Instantiate the audio threads
     SoundOutThread soundOutThread;
 
+    QSharedMemory *mem_jt9;
+
 //---------------------------------------------------- private functions
     void readSettings();
     void writeSettings();