What I found was that I was using System Scheduler to close Wxsim and the time I had set was too small once I had Use GFS for Advection ticked. It was thus incomplete and Wret got confused. I set a longer period, now not sure if Wxsim is closing itself or SS… but it now works with a 4min span. SS will only close t if it is hung or takes longer than 3 mins to run…