diff --git a/lib/jt9a.f90 b/lib/jt9a.f90
index 3ca567b81..f316a8226 100644
--- a/lib/jt9a.f90
+++ b/lib/jt9a.f90
@@ -18,12 +18,11 @@ subroutine jt9a()
   integer*1 attach_jt9
 !  integer*1 lock_jt9,unlock_jt9
   integer size_jt9
-  integer itime(8)
 ! Multiple instances:
   character*80 mykey
+  integer :: lun, stat
   type(dec_data), pointer :: shared_data
   type(params_block) :: local_params
-  logical fileExists
   volatile shared_data
 
 ! Multiple instances:
@@ -39,17 +38,19 @@ subroutine jt9a()
   i0 = len(mykey)
   i0=setkey_jt9(trim(mykey))
   i1=attach_jt9()
-  msdelay=1
+  msdelay=100
 
-! Wait here until the .lock file is removed by GUI
-10 inquire(file=trim(temp_dir)//'/.lock',exist=fileExists)
-  if(fileExists) then
+! Wait here until the .start file is created by GUI
+10 open(newunit=lun,file=trim(temp_dir)//'/.start',iostat=stat,status='old')
+  if(stat.ne.0) then
      call sleep_msec(msdelay)
      go to 10
   endif
+  close(unit=lun,status='delete')
 
-  inquire(file=trim(temp_dir)//'/.quit',exist=fileExists)
-  if(fileExists) then
+  open(newunit=lun,file=trim(temp_dir)//'/.quit',iostat=stat,status='old')
+  if(stat.eq.0) then
+     close(unit=lun,status='delete')
      i1=detach_jt9()
      go to 999
   endif
@@ -83,9 +84,12 @@ subroutine jt9a()
   call multimode_decoder(shared_data%ss,shared_data%id2,local_params,12000)
   call timer('decoder ',1)
 
-! Wait here until GUI routine decodeDone() has re-created the .lock file
-100 inquire(file=trim(temp_dir)//'/.lock',exist=fileExists)
-  if(fileExists) go to 10
+! Wait here until GUI routine decodeDone() has re-created the .start file
+100 open(newunit=lun,file=trim(temp_dir)//'/.stop',iostat=stat,status='old')
+  if(stat.eq.0) then
+     close(unit=lun,status='delete')
+     go to 10
+  endif
   call sleep_msec(msdelay)
   go to 100
 
diff --git a/widgets/mainwindow.cpp b/widgets/mainwindow.cpp
index 8c3905d98..8622a5213 100644
--- a/widgets/mainwindow.cpp
+++ b/widgets/mainwindow.cpp
@@ -1041,8 +1041,8 @@ void MainWindow::on_the_minute ()
 
 void MainWindow::pause_jt9 ()
 {
-  // Create .lock so jt9 will wait
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
+  // Create .stop so jt9 will wait
+  QFile l {m_config.temp_dir ().absoluteFilePath (".stop")};
   if (!l.open(QFile::ReadWrite))
     {
       MessageBox::warning_message (this, tr ("Error creating \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ()));
@@ -1051,21 +1051,11 @@ void MainWindow::pause_jt9 ()
 
 void MainWindow::release_jt9 ()
 {
-  // Remove .lock so jt9 will continue
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
-  while (l.exists ())
+  // Create .start so jt9 will continue
+  QFile l {m_config.temp_dir ().absoluteFilePath (".start")};
+  if (!l.open(QFile::ReadWrite))
     {
-      if (!l.remove ())
-        {
-          if (MessageBox::Cancel == MessageBox::query_message (this
-                                                               , tr ("IPC Error")
-                                                               , tr ("Error removing \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ())
-                                                               , QString {}
-                                                               , MessageBox::Retry | MessageBox::Cancel))
-            {
-              break;
-            }
-        }
+      MessageBox::warning_message (this, tr ("Error creating \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ()));
     }
 }
 
@@ -1108,21 +1098,6 @@ void MainWindow::stop_jt9 ()
     }
 }
 
-void MainWindow::cleanup_jt9 ()
-{
-  // Remove .quit as no longer needed
-  QFile l {m_config.temp_dir ().absoluteFilePath (".lock")};
-  while (l.exists ())
-    {
-      if (!l.remove ())
-        {
-          MessageBox::query_message (this
-                                     , tr ("Error removing \"%1\" - %2").arg (l.fileName ()).arg (l.errorString ())
-                                     , tr ("Click OK to retry"));
-        }
-    }
-}
-
 //--------------------------------------------------- MainWindow destructor
 MainWindow::~MainWindow()
 {
diff --git a/widgets/mainwindow.h b/widgets/mainwindow.h
index 675e25a4a..c1f99df74 100644
--- a/widgets/mainwindow.h
+++ b/widgets/mainwindow.h
@@ -774,7 +774,6 @@ private:
   void pause_jt9 ();
   void release_jt9 ();
   void stop_jt9 ();
-  void cleanup_jt9 ();
 };
 
 extern int killbyname(const char* progName);