There was an easy fix for the problem.

go to %appdata%\Factorio

rename
blueprint-storage.dat to e.g. _blueprint-storage.dat or simply delete it

problem solved.. well your blueprints are gone but hey I can play

factorio-current.log I cannot load, create a new game or anything else but stay in the main menu.

As soon as I do, the game crashes.

when the game crashed the first time, I was playing on LAN with a friend. My pc was hosting.
I pressed the B key to enter blueprints, then copied a blueprint from ...