diff --git a/mainwindow.cpp b/mainwindow.cpp
index 332f3bb90..21811b517 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -180,6 +180,7 @@ MainWindow::MainWindow(QSharedMemory *shdmem, QWidget *parent) :
   m_repeatMsg=0;
   m_bRigOpen=false;
   m_secBandChanged=0;
+  m_bMultipleOK=false;
   decodeBusy(false);
 
   ui->xThermo->setFillBrush(Qt::green);
@@ -187,11 +188,13 @@ MainWindow::MainWindow(QSharedMemory *shdmem, QWidget *parent) :
   ui->labDist->setStyleSheet("border: 0px;");
 
 #ifdef WIN32
-  while(true) {
+  if(!m_bMultipleOK) {
+    while(true) {
       int iret=killbyname("jt9.exe");
       if(iret == 603) break;
       if(iret != 0) msgBox("KillByName return code: " +
                            QString::number(iret));
+    }
   }
 #endif
   mem_jt9 = shdmem;
@@ -395,6 +398,7 @@ void MainWindow::writeSettings()
   settings.setValue("73TxDisable",m_73TxDisable);
   settings.setValue("Runaway",m_runaway);
   settings.setValue("Tx2QSO",m_tx2QSO);
+  settings.setValue("MultipleOK",m_bMultipleOK);
   settings.endGroup();
 }
 
@@ -505,6 +509,8 @@ void MainWindow::readSettings()
   ui->actionRunaway_Tx_watchdog->setChecked(m_runaway);
   m_tx2QSO=settings.value("Tx2QSO",false).toBool();
   ui->actionTx2QSO->setChecked(m_tx2QSO);
+  m_bMultipleOK=settings.value("MultipleOK",false).toBool();
+  ui->actionAllow_multiple_instances->setChecked(m_bMultipleOK);
 
   if(!ui->actionLinrad->isChecked() && !ui->actionCuteSDR->isChecked() &&
     !ui->actionAFMHot->isChecked() && !ui->actionBlue->isChecked()) {
@@ -2614,3 +2620,8 @@ void MainWindow::rigOpen()
     delete rig;
   }
 }
+
+void MainWindow::on_actionAllow_multiple_instances_triggered(bool checked)
+{
+  m_bMultipleOK=checked;
+}
diff --git a/mainwindow.h b/mainwindow.h
index b08da9194..90b8fc43b 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -153,6 +153,8 @@ private slots:
   void killFile();
   void on_tuneButton_clicked();
 
+  void on_actionAllow_multiple_instances_triggered(bool checked);
+
 private:
     Ui::MainWindow *ui;
 
@@ -248,7 +250,7 @@ private:
     bool    m_tx2QSO;
     bool    m_tune;
     bool    m_bRigOpen;
-
+    bool    m_bMultipleOK;
     char    m_decoded[80];
 
     float   m_pctZap;
diff --git a/mainwindow.ui b/mainwindow.ui
index 09f68ae0e..a7d758a68 100644
--- a/mainwindow.ui
+++ b/mainwindow.ui
@@ -2058,6 +2058,12 @@ p, li { white-space: pre-wrap; }
     <property name="title">
      <string>Setup</string>
     </property>
+    <widget class="QMenu" name="menuAdvanced">
+     <property name="title">
+      <string>Advanced</string>
+     </property>
+     <addaction name="actionAllow_multiple_instances"/>
+    </widget>
     <addaction name="actionDeviceSetup"/>
     <addaction name="separator"/>
     <addaction name="actionMonitor_OFF_at_startup"/>
@@ -2074,6 +2080,8 @@ p, li { white-space: pre-wrap; }
     <addaction name="action_73TxDisable"/>
     <addaction name="actionRunaway_Tx_watchdog"/>
     <addaction name="actionTx2QSO"/>
+    <addaction name="separator"/>
+    <addaction name="menuAdvanced"/>
    </widget>
    <widget class="QMenu" name="menuView">
     <property name="title">
@@ -2631,6 +2639,14 @@ p, li { white-space: pre-wrap; }
     <string>Tx messages echoed to QSO window</string>
    </property>
   </action>
+  <action name="actionAllow_multiple_instances">
+   <property name="checkable">
+    <bool>true</bool>
+   </property>
+   <property name="text">
+    <string>Allow multiple instances</string>
+   </property>
+  </action>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <customwidgets>