diff --git a/src/Handler/Course/ParticipantInvite.hs b/src/Handler/Course/ParticipantInvite.hs
index 3714c303e..857cbda7f 100644
--- a/src/Handler/Course/ParticipantInvite.hs
+++ b/src/Handler/Course/ParticipantInvite.hs
@@ -73,36 +73,42 @@ postCAddUserR tid ssh csh = do
            | otherwise
              = CourseR tid ssh csh CUsersR
   formResultModal usersToRegister dest $ \AddUsers{..} -> hoist runDBJobs $ do
-    uids <- registerUsers cid auUsers
-    for_ auTutorial $ \tutorialName -> lift $ do
-      -- TODO: move somewhere else
-      now <- liftIO getCurrentTime
-      Entity tutId _ <- upsert
-        Tutorial
-          { tutorialCourse = cid
-          , tutorialType = CI.mk mempty -- TODO: remove type? unneeded?
-          , tutorialCapacity = Nothing
-          , tutorialRoom = Nothing
-          , tutorialRoomHidden = False
-          , tutorialTime = Occurrences mempty mempty
-          , tutorialRegGroup = Nothing -- TODO: remove
-          , tutorialRegisterFrom = Nothing
-          , tutorialRegisterTo = Nothing
-          , tutorialDeregisterUntil = Nothing
-          , tutorialLastChanged = now
-          , tutorialTutorControlled = False
-          , ..
-          }
-        [ TutorialName        =. tutorialName
-        , TutorialLastChanged =. now
-        ]
-      for_ uids $ \tutorialParticipantUser -> upsert
-        TutorialParticipant
-          { tutorialParticipantTutorial = tutId
-          , ..
-          }
-        []
-      -- tell . pure <=< messageI Success . MsgCourseParticipantsRegisteredTutorial $ length uids
+    avsUsers :: Map Text (Maybe UserId) <- sequenceA . flip Map.fromSet auUsers $ liftHandler . upsertAvsUser
+    let retrievedUsers = catMaybes $ Map.elems avsUsers
+    if
+      | uids@(_:_) <- retrievedUsers -> do
+        registerUsers cid avsUsers
+        for_ auTutorial $ \tutorialName -> lift $ do
+          -- TODO: move somewhere else
+          now <- liftIO getCurrentTime
+          Entity tutId _ <- upsert
+            Tutorial
+              { tutorialCourse = cid
+              , tutorialType = CI.mk mempty -- TODO: remove type? unneeded?
+              , tutorialCapacity = Nothing
+              , tutorialRoom = Nothing
+              , tutorialRoomHidden = False
+              , tutorialTime = Occurrences mempty mempty
+              , tutorialRegGroup = Nothing -- TODO: remove
+              , tutorialRegisterFrom = Nothing
+              , tutorialRegisterTo = Nothing
+              , tutorialDeregisterUntil = Nothing
+              , tutorialLastChanged = now
+              , tutorialTutorControlled = False
+              , ..
+              }
+            [ TutorialName        =. tutorialName
+            , TutorialLastChanged =. now
+            ]
+          for_ uids $ \tutorialParticipantUser -> upsert
+            TutorialParticipant
+              { tutorialParticipantTutorial = tutId
+              , ..
+              }
+            []
+          -- tell . pure <=< messageI Success . MsgCourseParticipantsRegisteredTutorial $ length uids
+      | otherwise
+        -> tell . pure =<< messageI Error MsgCourseParticipantsRegisterNoneGiven
 
   let heading = prependCourseTitle tid ssh csh MsgCourseParticipantsRegisterHeading
 
@@ -114,19 +120,17 @@ postCAddUserR tid ssh csh = do
       }
 
 
-registerUsers :: CourseId -> Set Text -> WriterT [Message] (YesodJobDB UniWorX) [UserId]
-registerUsers cid auUsers = do
-  avsUsers :: Map Text (Maybe UserId) <- sequenceA . flip Map.fromSet auUsers $
-    liftHandler . upsertAvsUser -- TODO: upsertAvsUser should return whole Entity
+--confirmAddUser :: ()
+--confirmAddUser = do
+--  siteLayoutMsg MsgCourseParticipantsRegisterConfirmationHeading $ do
+--    setTitleI MsgCourseParticipantsRegisterConfirmationHeading
 
-  if
-    | null avsUsers
-      -> tell . pure =<< messageI Error MsgCourseParticipantsRegisterNoneGiven
-    | otherwise
-      -- register retrieved users
-      -> tell <=< lift . addParticipantsResultMessages <=< lift . execWriterT . mapM_ (registerUser cid) $ Map.toList avsUsers
 
-  return . catMaybes $ Map.elems avsUsers
+
+registerUsers :: CourseId -> Map Text (Maybe UserId) -> WriterT [Message] (YesodJobDB UniWorX) ()
+registerUsers cid users
+  | null users = tell . pure =<< messageI Error MsgCourseParticipantsRegisterNoneGiven
+  | otherwise = tell <=< lift . addParticipantsResultMessages <=< lift . execWriterT . mapM_ (registerUser cid) $ Map.toList users
 
 
 addParticipantsResultMessages :: (MonadHandler m, HandlerSite m ~ UniWorX)