The mod Construction Drones caused a non-recoverable error.
Please report this error to the mod author.

Error while running event Construction_Drones::on_configuration_changed
Construction_Drones/script/construction_drone.lua:114: bad argument #1 of 2 to 'pairs' (table expected, got nil)
stack traceback:
[C]: in function 'pairs'
Construction_Drones/script/construction_drone.lua:114: in function 'get_characters'
Construction_Drones/script/construction_drone.lua:127: in function 'get_characters_for_entity'
Construction_Drones/script/construction_drone.lua:666: in function 'find_a_character'
Construction_Drones/script/construction_drone.lua:2287: in function <Construction_Drones/script/construction_drone.lua:2217>
(...tail calls...)
Construction_Drones/script/construction_drone.lua:689: in function 'set_drone_idle'
Construction_Drones/script/construction_drone.lua:2525: in function 'on_configuration_changed'
Construction_Drones/control.lua:67: in function <Construction_Drones/control.lua:64>

I see logistic beacons removed, etc. May be related to that, I was loading a game that I was playing for a while using these features...

I've got it working now. Removed Mod, loaded game and allowed everything to be removed, then saved it and added Mod again. Needed to research again, but working fine now, once I used ALT-R to toggle the (non-existent) roboport. :-)

Also added Repair Turrets, which is what I was mostly using these for at this point in my game.

Love your Mods, thank you for working on them!