diff --git a/toonz/sources/toonz/main.cpp b/toonz/sources/toonz/main.cpp
index 3c9d6a6..054717f 100644
--- a/toonz/sources/toonz/main.cpp
+++ b/toonz/sources/toonz/main.cpp
@@ -233,7 +233,7 @@ project->setUseScenePath(TProject::Extras, false);
   // Imposto la rootDir per ImageCache
 
   /*-- TOONZCACHEROOTの設定  --*/
-  TFilePath cacheDir               = ToonzFolder::getCacheRootFolder();
+  TFilePath cacheDir = ToonzFolder::getCacheRootFolder();
   if (cacheDir.isEmpty()) cacheDir = TEnv::getStuffDir() + "cache";
   TImageCache::instance()->setRootDir(cacheDir);
 }
@@ -319,10 +319,10 @@ int main(int argc, char *argv[]) {
   QApplication a(argc, argv);
 
 #ifdef MACOSX
-// This workaround is to avoid missing left button problem on Qt5.6.0.
-// To invalidate m_rightButtonClicked in Qt/qnsview.mm, sending
-// NSLeftButtonDown event before NSLeftMouseDragged event propagated to
-// QApplication. See more details in ../mousedragfilter/mousedragfilter.mm.
+  // This workaround is to avoid missing left button problem on Qt5.6.0.
+  // To invalidate m_rightButtonClicked in Qt/qnsview.mm, sending
+  // NSLeftButtonDown event before NSLeftMouseDragged event propagated to
+  // QApplication. See more details in ../mousedragfilter/mousedragfilter.mm.
 
 #include "mousedragfilter.h"
 
@@ -622,7 +622,8 @@ int main(int argc, char *argv[]) {
 
 #ifdef _WIN32
   // http://doc.qt.io/qt-5/windows-issues.html#fullscreen-opengl-based-windows
-  QWindowsWindowFunctions::setHasBorderInFullScreen(w.windowHandle(), true);
+  if (w.windowHandle())
+    QWindowsWindowFunctions::setHasBorderInFullScreen(w.windowHandle(), true);
 #endif
 
   splash.showMessage(offsetStr + "Loading style sheet ...", Qt::AlignCenter,