Factorio v1.1.34
Mod version 1.0.21

41.976 Error ControlSettings.cpp:220: follow-drone (custom-input): unknown key_sequence: return
41.979 Custom inputs active: 82
41.980 Factorio initialised
42.001 Mods to disable:Failed to load mods: Error while loading entity prototype "companion-construction-robot" (construction-robot): Key "direction_count" not found in property tree at ROOT.construction-robot.companion-construction-robot.idle
Modifications: Companion Drones

Mods to be disabled:
• Companion_Drones (1.0.21)

Duplicate of https://mods.factorio.com/mod/Companion_Drones/discussion/60799ec3d953a49aa42c5186

Got the same error and I narrowed it down to a mod called "Teleporters". Once disabled everything was fine.

https://mods.factorio.com/mod/Teleporters

Hope this helps.

In my case it happened after I updated another mod, but in a running game, so not a fixed incompatibility. If it was similar for you, try this:
Disable Companion Drones, enable Teleporters, start the game. Load your save, get out (without saving). Enable Companion Drones, see if the game starts.

In my case it happens after every Space Exploration update, and I just disable companion drones, start Factorio, enable companion drones, restart it, it works.