diff --git a/messages/uniworx/de-de-formal.msg b/messages/uniworx/de-de-formal.msg
index 3b5a526a4..6d7a40635 100644
--- a/messages/uniworx/de-de-formal.msg
+++ b/messages/uniworx/de-de-formal.msg
@@ -1186,7 +1186,7 @@ MenuTutorialEdit: Tutorium editieren
 MenuTutorialComm: Mitteilung an Teilnehmer
 MenuExamList: Prüfungen
 MenuExamNew: Neue Prüfung anlegen
-MenuExamEdit: Bearbeiten
+MenuExamEdit: Prüfung bearbeiten
 MenuExamUsers: Teilnehmer
 MenuExamGrades: Prüfungsleistungen
 MenuExamAddMembers: Prüfungsteilnehmer hinzufügen
@@ -1402,7 +1402,6 @@ ExamCorrectHeading examname@Text: Prüfungsergebnisse für #{examname} eintragen
 
 ExamCorrectHeadDate: Zeit
 ExamCorrectHeadParticipant: Teilnehmer
-ExamCorrectHeadParticipantTooltip: 
 ExamCorrectHeadPart exampartnum@ExamPartNumber: #{exampartnum}
 ExamCorrectHeadPartName exampartname@ExamPartName: #{exampartname}
 ExamCorrectHeadStatus: Status
@@ -1411,6 +1410,8 @@ ExamCorrectButtonSend: Senden
 
 ExamCorrectErrorMultipleMatchingParticipants: Dem Identifikator konnten mehrere Prüfungsteilnehmer zugeordnet werden.
 ExamCorrectErrorNoMatchingParticipants: Dem Identifikator konnte kein Prüfungsteilnehmer zugeordnet werden.
+ExamCorrectErrorPartResultOutOfBounds examPartNumber@ExamPartNumber: Prüfungsergebnis für Teil #{examPartNumber} ist nicht größer Null.
+ExamCorrectErrorPartResultOutOfBoundsMax examPartNumber@ExamPartNumber maxPoints@Points: Prüfungsergebnis für Teil #{examPartNumber} liegt nicht zwischen 0 und #{maxPoints}.
 
 SubmissionUserInvitationAccepted shn@SheetName: Sie wurden als Mitabgebende(r) für eine Abgabe zu #{shn} eingetragen
 SubmissionUserInvitationDeclined shn@SheetName: Sie haben die Einladung, Mitabgebende(r) für #{shn} zu werden, abgelehnt
diff --git a/messages/uniworx/en-eu.msg b/messages/uniworx/en-eu.msg
index e0ae2c93b..12f3e62eb 100644
--- a/messages/uniworx/en-eu.msg
+++ b/messages/uniworx/en-eu.msg
@@ -1185,7 +1185,7 @@ MenuTutorialEdit: Edit tutorial
 MenuTutorialComm: Send course message
 MenuExamList: Exams
 MenuExamNew: Create new exam
-MenuExamEdit: Edit
+MenuExamEdit: Edit exam
 MenuExamUsers: Participants
 MenuExamGrades: Exam results
 MenuExamAddMembers: Add exam participants
@@ -1408,6 +1408,8 @@ ExamCorrectButtonSend: Submit
 
 ExamCorrectErrorMultipleMatchingParticipants: This identifier matches on multiple exam participants.
 ExamCorrectErrorNoMatchingParticipants: This identifier does not match on any exam participant.
+ExamCorrectErrorPartResultOutOfBounds examPartNumber: Exam part result for #{examPartNumber} ist not greater zero.
+ExamCorrectErrorPartResultOutOfBoundsMax examPartNumber maxPoints: Exam part result for #{examPartNumber} is not between 0 and #{maxPoints}.
 
 SubmissionUserInvitationAccepted shn: You now participate in a submission for #{shn}
 SubmissionUserInvitationDeclined shn: You have declined the invitation to participate in a submission for #{shn}
@@ -1629,6 +1631,7 @@ ExamFormCorrection: Correction
 ExamFormParts: Exam parts
 
 ExamCorrectors: Correctors
+ExamCorrectorsTip: Correctors configured here may, after the start of the exam and until "Results visible from", enter exam part results for all exam parts and participants.
 ExamCorrectorAlreadyAdded: A corrector with this email address already exists
 
 ExamParts: Exam parts/questions
diff --git a/src/Handler/Exam/Correct.hs b/src/Handler/Exam/Correct.hs
index 37c2a24c4..35736c4c8 100644
--- a/src/Handler/Exam/Correct.hs
+++ b/src/Handler/Exam/Correct.hs
@@ -38,7 +38,8 @@ data CorrectInterfaceResponse
     , ciraMessage    :: Text
     }
   | CorrectInterfaceResponseFailure
-    { cirfMessage    :: Text
+    { cirfUser       :: Maybe CorrectInterfaceUser
+    , cirfMessage    :: Text
     }
   | CorrectInterfaceResponseNoOp
     { cirnUsers      :: Set CorrectInterfaceUser
@@ -103,11 +104,11 @@ postECorrectR tid ssh csh examn = do
 
   CorrectInterfaceRequest{..} <- requireCheckJsonBody
 
-  response <- runDB $ do
-    Entity eId Exam{..} <- fetchExam tid ssh csh examn
+  response <- exceptT return return . hoist runDB $ do
+    Entity eId Exam{..} <- lift $ fetchExam tid ssh csh examn
     euid <- traverse decrypt ciqUser
 
-    participantMatches <- E.select . E.from $ \(examRegistration `E.InnerJoin` user) -> do
+    participantMatches <- lift . E.select . E.from $ \(examRegistration `E.InnerJoin` user) -> do
       E.on $ examRegistration E.^. ExamRegistrationUser E.==. user E.^. UserId
       E.where_ $ examRegistration E.^. ExamRegistrationExam E.==. E.val eId
 
@@ -150,10 +151,10 @@ postECorrectR tid ssh csh examn = do
         now <- liftIO getCurrentTime
         newExamPartResults <- if
           | Just results <- ciqResults -> iforM (toNullable results) $ \partNumber mPartResult -> do
-            (Entity examPartId ExamPart{..}) <- getBy404 $ UniqueExamPartNumber eId partNumber
-            mOldResult <- getBy $ UniqueExamPartResult examPartId uid
+            (Entity examPartId ExamPart{..}) <- lift . getBy404 $ UniqueExamPartNumber eId partNumber
+            mOldResult <- lift . getBy $ UniqueExamPartResult examPartId uid
             if
-              | Just (Entity oldId _) <- mOldResult, is _Nothing mPartResult -> do
+              | Just (Entity oldId _) <- mOldResult, is _Nothing mPartResult -> lift $ do
                 delete oldId
                 audit $ TransactionExamPartResultDeleted examPartId uid
                 return Nothing
@@ -162,29 +163,36 @@ postECorrectR tid ssh csh examn = do
                   mNew = ExamAttended <$> mPartResult
                   resultVal = _entityVal . _examPartResultResult
                 in if
-                  | mOld /= mNew -> let
-                      -- cut off part results that exceed the maximum number of points for this exam part for now
-                      -- TODO answer with new failure response type instead
-                      partResult' = if
-                        | Just maxPts <- examPartMaxPoints, maxPts < partResult -> maxPts
-                        | otherwise -> partResult
-                    in do
-                      newExamPartResult <- upsert ExamPartResult
+                  | mOld /= mNew -> do
+                      let
+                        partResultAcceptable = 0 <= partResult
+                                            && maybe True (partResult <=) examPartMaxPoints
+                      guardMExceptT partResultAcceptable $
+                        let
+                          msg | Just maxPoints <- examPartMaxPoints
+                              = MsgExamCorrectErrorPartResultOutOfBoundsMax partNumber maxPoints
+                              | otherwise
+                              = MsgExamCorrectErrorPartResultOutOfBounds partNumber
+                         in CorrectInterfaceResponseFailure
+                              <$> (Just <$> userToResponse match)
+                              <*> (getMessageRender <*> pure msg)
+                      
+                      newExamPartResult <- lift $ upsert ExamPartResult
                         { examPartResultExamPart    = examPartId
                         , examPartResultUser        = uid
-                        , examPartResultResult      = ExamAttended partResult'
+                        , examPartResultResult      = ExamAttended partResult
                         , examPartResultLastChanged = now
                         }
-                        [ ExamPartResultResult      =. ExamAttended partResult'
+                        [ ExamPartResultResult      =. ExamAttended partResult
                         , ExamPartResultLastChanged =. now
                         ]
-                      audit $ TransactionExamPartResultEdit examPartId uid
+                      lift . audit $ TransactionExamPartResultEdit examPartId uid
                       return $ newExamPartResult ^? resultVal
                   | otherwise -> return $ mOldResult ^? _Just . resultVal
               | otherwise -> return Nothing
             | otherwise -> return mempty
 
-        newExamResult <- do
+        newExamResult <- lift $ do
           mOldResult <- getBy $ UniqueExamResult eId uid
           if
             | Just (Entity oldId _) <- mOldResult, is _Nothing ciqGrade -> do
@@ -222,7 +230,8 @@ postECorrectR tid ssh csh examn = do
 
       -- on match with no exam participant, answer with 400
       | [] <- participantMatches -> return CorrectInterfaceResponseFailure
-        { cirfMessage   = mr MsgExamCorrectErrorNoMatchingParticipants
+        { cirfUser      = Nothing
+        , cirfMessage   = mr MsgExamCorrectErrorNoMatchingParticipants
         }
 
       -- on match with multiple exam participants, answer with 400 and a set of all matches