diff --git a/keyboard/_darwinkeyboard.py b/keyboard/_darwinkeyboard.py
index 85670eed..c8b4b5e6 100644
--- a/keyboard/_darwinkeyboard.py
+++ b/keyboard/_darwinkeyboard.py
@@ -335,7 +335,10 @@ def map_char(self, character):
             return (128+self.media_keys[character],[])
         else:
             return self.key_map.character_to_vk(character)
+        
     def map_scan_code(self, scan_code):
+        if scan_code == 0xff:
+            return "UNKNOWN"
         if scan_code >= 128:
             character = [k for k, v in enumerate(self.media_keys) if v == scan_code-128]
             if len(character):
@@ -439,4 +442,4 @@ def type_unicode(character):
     # Key up
     event = Quartz.CGEventCreateKeyboardEvent(OUTPUT_SOURCE, 0, False)
     Quartz.CGEventKeyboardSetUnicodeString(event, len(character.encode('utf-16-le')) // 2, character)
-    Quartz.CGEventPost(Quartz.kCGSessionEventTap, event)
\ No newline at end of file
+    Quartz.CGEventPost(Quartz.kCGSessionEventTap, event)