diff --git a/Marlin/Conditionals_LCD.h b/Marlin/Conditionals_LCD.h
index 31ba12e4b..6632031a0 100644
--- a/Marlin/Conditionals_LCD.h
+++ b/Marlin/Conditionals_LCD.h
@@ -376,9 +376,10 @@
 
   #define HAS_DEBUG_MENU ENABLED(LCD_PROGRESS_BAR_TEST)
 
-  // MK2 Multiplexer forces SINGLENOZZLE to be enabled
+  // MK2 Multiplexer forces SINGLENOZZLE and kills DISABLE_INACTIVE_EXTRUDER
   #if ENABLED(MK2_MULTIPLEXER)
     #define SINGLENOZZLE
+    #undef DISABLE_INACTIVE_EXTRUDER
   #endif
 
   /**