The mod Updated Construction Drones - Forked (1.1.7) caused a non-recoverable error.
Please report this error to the mod author.
Error while running event Construction_Drones_Forked::on_player_left_game (ID 52)
Construction_Drones_Forked/script/command_processor.lua:838: attempt to index field 'character' (a nil value)
stack traceback:
Construction_Drones_Forked/script/command_processor.lua:838: in function 'process_return_to_player_command'
Construction_Drones_Forked/script/drone_manager.lua:156: in function 'set_drone_idle'
Construction_Drones_Forked/script/drone_manager.lua:401: in function 'cancel_player_drone_orders'
Construction_Drones_Forked/script/event_processor.lua:347: in function 'handler'
core/lualib/event_handler.lua:72: in function <core/lualib/event_handler.lua:70>
I can load the previous autosave, but the one created manually fails (about 2 minutes of game play later).