diff --git a/src/Cron.hs b/src/Cron.hs
index 4697c4bf8..1d1abec41 100644
--- a/src/Cron.hs
+++ b/src/Cron.hs
@@ -116,9 +116,10 @@ genMatch :: Int -- ^ Period
 genMatch p m z st CronMatchAny = take p $ map (bool id (bool succ id z . (`mod` fromIntegral p) . bool pred id z) m) [st..]
 genMatch _ _ _ _ CronMatchNone = []
 genMatch p m z _ (CronMatchSome xs) = take p . map (bool id (bool succ id z . (`mod` fromIntegral p) . bool pred id z) m) . Set.toAscList $ toNullable xs
-genMatch p m z st (CronMatchStep step) = do
+genMatch p m z st (CronMatchStep step) = do   
+  guard $ step /= 0
   start <- [st..st + step]
-  guard $ (start `mod` step) == 0
+  guard $ (start `mod` step) == 0 
   take (ceiling $ fromIntegral p % step) $ map (bool id (bool succ id z . (`mod` fromIntegral p) . bool pred id z) m) [start,start + step..]
 genMatch p m z st (CronMatchContiguous from to) = take p . map (bool id (bool succ id z . (`mod` fromIntegral p) . bool pred id z) m) $ [max st from..to]
 genMatch _ _ _ _ (CronMatchIntersect CronMatchNone _) = []
diff --git a/src/Jobs/Handler/Files.hs b/src/Jobs/Handler/Files.hs
index d304ebd2f..2e5588a81 100644
--- a/src/Jobs/Handler/Files.hs
+++ b/src/Jobs/Handler/Files.hs
@@ -275,7 +275,7 @@ dispatchJobInjectFiles = JobHandlerException . maybeT_ $ do
                    -> Handler (Sum Natural, Sum Word64)
     injectOrDelete (objInfo, fRef) = do
       let obj = Minio.oiObject objInfo
-          sz  = fromIntegral $ Minio.oiSize objInfo
+          sz  = fromIntegral $ max 1 $ Minio.oiSize objInfo
       
       fRef' <- runDB $ do
         logger <- askLoggerIO
diff --git a/src/Jobs/HealthReport.hs b/src/Jobs/HealthReport.hs
index 54e0317ec..a53dc8616 100644
--- a/src/Jobs/HealthReport.hs
+++ b/src/Jobs/HealthReport.hs
@@ -119,7 +119,9 @@ dispatchHealthCheckLDAPAdmins = fmap HealthLDAPAdmins . yesodTimeout (^. _appHea
           let hCampusExc :: CampusUserException -> Handler (Sum Integer)
               hCampusExc err = mempty <$ $logErrorS "healthCheckLDAPAdmins" (adminIdent <> ": " <> tshow err)
            in handle hCampusExc $ Sum 1 <$ campusUserReTest ldapPool ((>= reTestAfter) . realToFrac) FailoverUnlimited (Creds apLdap adminIdent [])
-        return $ numResolved % numAdmins
+        if numAdmins == 0
+          then return 0
+          else return $ numResolved % numAdmins
     _other -> return Nothing