diff --git a/vobject/ics_diff.py b/vobject/ics_diff.py
index 6d48e3b..871641c 100644
--- a/vobject/ics_diff.py
+++ b/vobject/ics_diff.py
@@ -91,7 +91,11 @@ def processComponentLists(leftList, rightList):
                     matchResult = processComponentPair(comp, rightComp)
                     if matchResult is not None:
                         output.append(matchResult)
-
+                        
+        while rightIndex < rightListSize:
+            output.append((None, rightList[rightIndex]))
+            rightIndex += 1
+            
         return output
 
     def newComponent(name, body):