I've tried to recreate this crash-uninstall thing without any progress.

I've tried to crash the cpu while playing (over OC)
crashed graphics card (over OC)

game is still installed in steam after these crashes. so im unable to recreate this problems

I assume this could be due to a bad section or ...

so.. I had 207 hours played in one massive world, and Factorio/Steam almost made me cry when they was gone for like 5minutes (read whole post)

short version
I was playing Factorio when the computer restarted. Steam did not find Factorio after restart. Got panic and reinstalled game.

longer ...