diff --git a/companion/src/helpers.cpp b/companion/src/helpers.cpp
index e59e39c11..e895d9c29 100644
--- a/companion/src/helpers.cpp
+++ b/companion/src/helpers.cpp
@@ -371,6 +371,31 @@ void startSimulation(QWidget * parent, RadioData & radioData, int modelIdx)
     simuData->setCurrentModel(modelIdx);
   }
 
+#ifdef __APPLE__
+  SimulatorMainWindow * dialog = new SimulatorMainWindow(parent, simulatorId, flags);
+  dialog->setWindowModality(Qt::ApplicationModal);
+  dialog->setAttribute(Qt::WA_DeleteOnClose);
+
+  QObject::connect(dialog, &SimulatorMainWindow::destroyed, [simuData] (void) {
+    simulatorRunning = false;
+    // TODO simuData and Horus tmp directory is deleted on simulator close OR we could use it to get back data from the simulation
+    delete simuData;
+  });
+
+  QString resultMsg;
+  if (dialog->getExitStatus(&resultMsg)) {
+    if (resultMsg.isEmpty())
+      resultMsg = QCoreApplication::translate("Companion", "Uknown error during Simulator startup.");
+    QMessageBox::critical(NULL, QCoreApplication::translate("Companion", "Simulator Error"), resultMsg);
+    dialog->deleteLater();
+  } else if (dialog->setRadioData(simuData)) {
+    simulatorRunning = true;
+    dialog->show();
+  } else {
+    QMessageBox::critical(NULL, QCoreApplication::translate("Companion", "Data Load Error"), QCoreApplication::translate("Companion", "Error occurred while starting simulator."));
+    dialog->deleteLater();
+  }
+#else
   // the directory will be automatically deleted when QTemporaryDir goes out of scope
   QTemporaryDir tmpDir(QDir::tempPath() + "/etx-XXXXXX");
   if (tmpDir.isValid()) {
@@ -427,7 +452,7 @@ void startSimulation(QWidget * parent, RadioData & radioData, int modelIdx)
 
   if (simuData)
     delete simuData;
-
+#endif
 }
 
 QPixmap makePixMap(const QImage & image)
diff --git a/radio/src/gui/colorlcd/libui/bitmapbuffer_fileio.cpp b/radio/src/gui/colorlcd/libui/bitmapbuffer_fileio.cpp
index 9f6e497cb..6df40ef95 100644
--- a/radio/src/gui/colorlcd/libui/bitmapbuffer_fileio.cpp
+++ b/radio/src/gui/colorlcd/libui/bitmapbuffer_fileio.cpp
@@ -61,6 +61,7 @@ void *stb_realloc(void *ptr, unsigned int oldsz, unsigned int newsz)
 #define STBI_NO_STDIO
 #define STBI_NO_LINEAR
 #define STB_IMAGE_IMPLEMENTATION
+#define STBI_NO_THREAD_LOCALS
 #include "stb/stb_image.h"
 
 // fill 'data' with 'size' bytes.  return number of bytes actually read