diff --git a/src/com/android/phone/NotificationMgr.java b/src/com/android/phone/NotificationMgr.java
index 4fb96a2..188baaa 100644
--- a/src/com/android/phone/NotificationMgr.java
+++ b/src/com/android/phone/NotificationMgr.java
@@ -439,7 +439,10 @@
                 mUserManager.getSerialNumbersOfUsers(/* excludeDying= */ true);
         List<UserHandle> users = new ArrayList<>(serialNumbersOfUsers.length);
         for (long serialNumber : serialNumbersOfUsers) {
-            users.add(mUserManager.getUserForSerialNumber(serialNumber));
+            UserHandle userHandle = mUserManager.getUserForSerialNumber(serialNumber);
+            if (userHandle != null) {
+                users.add(userHandle);
+            }
         }
         return users;
     }