I'm having the same hard crash except with Factory Planner.
The mod GUI Unifyer - Forked (1.12.1) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event GUI_Unifyer_forked::on_nth_tick(6)
Unknown position: factoryplanner_mainframe
stack traceback:
[C]: in function 'index'
__GUI_Unifyer_forked/control.lua:106: in function 'change_one_icon'
GUI_Unifyer_forked/control.lua:149: in function 'fix_buttons'
GUI_Unifyer_forked/control.lua:774: in function <GUI_Unifyer_forked/control.lua:760>
It seems to occur when a research finishes. I could reproducibly cause the error by reloading the same autosave, happens when the research completes, however it only happens when the screensaver from the Trainsaver mod is running. If the trainsaver isn't currently going and I'm in control of my character like normal the crash doesn't occur. Wonder if it has something to do with how the icons in the top left are hidden while the trainsaver is active? Not sure if this is a bug for the Trainsaver dev to fix since it doesn't occur when the trainsaver isn't on the screen but the error is saying GUI Unifyer causes it so I'm posting here.
Same crash can also be reproduced identically using the non-forked GUI Unifier original mod.
