I just downloaded the latest Free version of this game in the last 3 or 4 days. Periodically it'll flash black screen and minimize. When you enlarge it full screen again it'll Start Screen with Load/Save.
It 's hard to find your posting here, if you reply to a 1 year old topic. Looks like you clicked the wrong reply button. What version you have downloaded? win32, win64, mac, linux, android. Looks like your system has some problems on gfx or some other programms on your system force HOS to minimize. Try options in HOS and toogle fullscreen off. Win 10 has also some nasty problems with dual monitoring and some grafic cards on fullscreen mode. So if your system is a dual monitor you can also try to reduce it temporary to one monitor before starting HOS.