diff --git a/Ganeti/HTools/QC.hs b/Ganeti/HTools/QC.hs
index d57ae48175e071450e35e8c2a539bc5fb7b21534..a9af42bb7097e6f624891ee6d865783a686922c1 100644
--- a/Ganeti/HTools/QC.hs
+++ b/Ganeti/HTools/QC.hs
@@ -680,6 +680,7 @@ prop_Loader_lookupInstanceIdx kti inst =
         findIndex (\p -> fst p == inst) kti) of
     (Nothing, Nothing) -> True
     (Just idx, Just ex) -> idx == snd (kti !! ex)
+    _ -> False
 
 prop_Loader_assignIndices enames =
   length nassoc == length enames &&