@Wielder / @Atali are you absolutely sure you aren’t using mods?
(Mods will likely reinstall if you were subscribed to them just like any DLC or other game content, even if you freshly install the game)
To be certain, right-click the game in Steam, select Manage → Browse local files and in the SonanSandbox\Mods folder see if there is anything at all in your modlist.txt (delete it for good measure)
I am asking because just a few days ago we had the thread with somebody having the same issue, @Wielder posted even there.
In any case, even if the cause is not the mod, the reason for the crash seems very similar, in which case there will be a note about it in your log, open it up in notepad and search for the text “Could not find a key mapping to match” in your ConanSandbox\Saved\Logs\ConanSandbox.log file right after the crash (you can just post the log file here so we can all look, including Funcom staff 