diff --git a/Sources/MAKVONotificationCenter/MAKVONotificationCenter.m b/Sources/MAKVONotificationCenter/MAKVONotificationCenter.m
index 3d16875..c06b8f8 100644
--- a/Sources/MAKVONotificationCenter/MAKVONotificationCenter.m
+++ b/Sources/MAKVONotificationCenter/MAKVONotificationCenter.m
@@ -191,6 +191,7 @@ - (void)deregister
     _observer = nil;
     _target = nil;
     _keyPaths = nil;
+    _userInfo = nil;
 }
 
 - (BOOL)isValid	// the observation is invalid if and only if it has been deregistered