diff --git a/Marlin/Conditionals.h b/Marlin/Conditionals.h
index baa822d7f..ff6c6b187 100644
--- a/Marlin/Conditionals.h
+++ b/Marlin/Conditionals.h
@@ -24,4 +24,4 @@
  * Conditionals.h
  * OBSOLETE: Replaced by Conditionals_LCD.h and Conditionals_post.h
  */
-#include "SanityCheck.h"
+#error "Old configurations? Please delete all #include lines from Configuration.h and Configuration_adv.h."
diff --git a/Marlin/MarlinSerial.cpp b/Marlin/MarlinSerial.cpp
index d2f5623cb..304b3be07 100644
--- a/Marlin/MarlinSerial.cpp
+++ b/Marlin/MarlinSerial.cpp
@@ -451,7 +451,7 @@ MarlinSerial customizedSerial;
 #if ENABLED(EMERGENCY_PARSER)
 
   // Currently looking for: M108, M112, M410
-  // If you alter the parser please don't forget to update the capabilities in Conditionals.h
+  // If you alter the parser please don't forget to update the capabilities in Conditionals_post.h
 
   FORCE_INLINE void emergency_parser(unsigned char c) {