When leaving the game since 1.6,1 and choosing the Save & Exit button it appears to hang. Normally it would change the screen and show a progress of the save. It freezes on the menu screen, but it does eventually report "done". and I'm able to exit. It does seem it takes longer but that maybe due to the fact that I'm staring at a frozen screen (i.e. watched pot never boils).

Not a critical issue since it is saving but is a little unnerving. 

9-21-18 I have turned on Auto Save and found if I wait until I see saving icon complete and then exit it works as expected. I don't know if that'll work every time but I'll routinely do that for now.

10-23-2018 This seems to be tied into a furnace array (was 41 furnaces but now only 33) I created even if it's turned off but was on within a few minutes of exiting. If it's been longer or I didn't use it at all I exit as expected.