diff --git a/messages/uniworx/de-de-formal.msg b/messages/uniworx/de-de-formal.msg
index 640a791f4..ff7a2f644 100644
--- a/messages/uniworx/de-de-formal.msg
+++ b/messages/uniworx/de-de-formal.msg
@@ -368,6 +368,7 @@ SheetWarnNoActiveTo: "Aktiv bis/Ende Abgabezeitraum" sollte stets angegeben werd
 SheetNoCurrent: Es gibt momentan kein aktives Übungsblatt.
 SheetNoOldUnassigned: Alle Abgaben inaktiver Blätter sind bereits einen Korrektor zugeteilt.
 SheetsUnassignable name@Text: Momentan keine Abgaben zuteilbar für #{name}
+SheetSubmissionModeNoneWithoutNotGraded: Es wurde "Keine Abgabe" eingestellt, jedoch nicht "Keine Bewertung". Kursteilnehmer werden nicht abgeben können.
 
 Deadline: Abgabe
 Done: Eingereicht
diff --git a/messages/uniworx/en-eu.msg b/messages/uniworx/en-eu.msg
index 372c993ee..5a28dab5c 100644
--- a/messages/uniworx/en-eu.msg
+++ b/messages/uniworx/en-eu.msg
@@ -367,6 +367,7 @@ SheetWarnNoActiveTo: “Active to/Submission period end” should always be spec
 SheetNoCurrent: There is no currently active exercise sheet
 SheetNoOldUnassigned: All submissions for inactive sheets are already assigned to correctors.
 SheetsUnassignable name: Submission for #{name} may not currently be assigned to correctors.
+SheetSubmissionModeNoneWithoutNotGraded: The sheet was configured to be "No submission" but not "Not marked". Course participants will not be able to submit.
 
 Deadline: Deadline
 Done: Submitted
diff --git a/src/Handler/Sheet/Form.hs b/src/Handler/Sheet/Form.hs
index 2705f7762..23f80effa 100644
--- a/src/Handler/Sheet/Form.hs
+++ b/src/Handler/Sheet/Form.hs
@@ -152,6 +152,10 @@ makeSheetForm cId msId template = identifyForm FIDsheet . validateForm validateS
 
       warnValidation MsgSheetWarnNoActiveTo $ is _Just sfActiveTo || is _Nothing sfActiveFrom
 
+      warnValidation MsgSheetSubmissionModeNoneWithoutNotGraded
+        $ classifySubmissionMode sfSubmissionMode /= SubmissionModeNone
+       || sfType == NotGraded
+
 correctorForm :: Loads -> AForm Handler Loads
 correctorForm loads' = wFormToAForm $ do
   currentRoute <- fromMaybe (error "correctorForm called from 404-handler") <$> liftHandler getCurrentRoute
diff --git a/src/Handler/Sheet/Show.hs b/src/Handler/Sheet/Show.hs
index 00f38c092..e4dea05ad 100644
--- a/src/Handler/Sheet/Show.hs
+++ b/src/Handler/Sheet/Show.hs
@@ -143,6 +143,12 @@ getSShowR tid ssh csh shn = do
       E.where_ $ psFile E.^. PersonalisedSheetFileUser E.==. E.val uid
            E.&&. psFile E.^. PersonalisedSheetFileSheet E.==. E.val sid
 
+  submissionModeNoneWithoutNotGradedWarning <- runMaybeT $ do
+    guard $ classifySubmissionMode (sheetSubmissionMode sheet) == SubmissionModeNone
+         && sheetType sheet /= NotGraded
+    guardM . hasWriteAccessTo $ CSheetR tid ssh csh shn SEditR
+    return $ notification NotificationBroad =<< messageI Warning MsgSheetSubmissionModeNoneWithoutNotGraded
+
   defaultLayout $ do
     setTitleI $ prependCourseTitle tid ssh csh $ SomeMessage shn
     let zipLink = CSheetR tid ssh csh shn SArchiveR
diff --git a/templates/sheetShow.hamlet b/templates/sheetShow.hamlet
index a6868a364..03bf14fdf 100644
--- a/templates/sheetShow.hamlet
+++ b/templates/sheetShow.hamlet
@@ -1,4 +1,7 @@
 $newline never
+$maybe warn <- submissionModeNoneWithoutNotGradedWarning 
+  ^{warn}
+
 $maybe descr <- sheetDescription sheet
   <section>
     <h2 #description>_{MsgSheetDescription}
@@ -19,10 +22,11 @@ $maybe descr <- sheetDescription sheet
         _{MsgSheetActiveFromParticipant}
       $else
         _{MsgSheetActiveFromParticipantNoSubmit}
-    $maybe ts <- sheetFrom
-      <dd .deflist__dd>#{ts}
-    $nothing
-      <dd .deflist__dd>_{MsgSheetActiveFromUnset}
+    <dd .deflist__dd>
+      $maybe ts <- sheetFrom
+        #{ts}
+      $nothing
+        _{MsgSheetActiveFromUnset}
     $if hasSubmission
       <dt .deflist__dt>_{MsgSheetActiveToParticipant}
       $maybe ts <- sheetTo