diff --git a/Assistant/Threads/Committer.hs b/Assistant/Threads/Committer.hs
index 33b92c7e53..b3258f7299 100644
--- a/Assistant/Threads/Committer.hs
+++ b/Assistant/Threads/Committer.hs
@@ -58,6 +58,7 @@ commitThread st changechan commitchan transferqueue dstatus = runEvery (Seconds
 				else refill readychanges
 		else refill changes
 	where
+		refill [] = noop
 		refill cs = do
 			debug thisThread
 				[ "delaying commit of"