Hello,
I already created a ticket for this, but after connecting to another already solved one, my new comment didn´t get an answer yet. It still counts as solved, so I thought it would be better to open a new one for it. I apologize in advance, if I just would have to wait longer.

The old ticket is: Minecraft: Java Edition / MC-174227

I reinstalled the game, having all left data cleared like (for example those in the roaming-folder). But it didn´t help.
I had a look at the logs, but no error-code is displayed. The latest log-file is attached.

Minecraft itself always stops working at around 90%, while starting. This happens in older versions of Minecraft too, although sometimes I´m able to get into it, but it then stops after a short duration.