Index: /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp
===================================================================
--- /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp	(revision 54077)
+++ /trunk/src/VBox/Frontends/VirtualBox/src/runtime/UIMachineView.cpp	(revision 54078)
@@ -549,6 +549,8 @@
                                           (uint32_t)(dScaleFactor * VBOX_OGL_SCALE_FACTOR_MULTIPLIER));
 
+#ifdef Q_WS_MAC
         /* Take backing scale-factor into account: */
         m_pFrameBuffer->setBackingScaleFactor(darwinBackingScaleFactor(machineWindow()));
+#endif /* Q_WS_MAC */
 
         /* Take unscaled HiDPI output mode into account: */