No, I think the issue is gone. I am not 100% sure because the bug only appeared occasionally and I couldn't figure out a reason for it or a way to reproduce it for you guys. But it didn't happen in some time now so I think it's gone.
If it happens again I will let you know.
Greetings
MikeMacho

I don't have the issue anymore. I reformatted my hard drive and reinstalled windows and all the drivers for some other reason. since then DayZ worked fine again.
Sorry that I didn't post here, that the issue has been resolved, I totally forgot about it.

No, I don't. It seems to just happen occasionally.

No, I play the game in fullscreen mode.

Hey Geez, thanks for the quick reply!
I didn't try verifying the game cache until now, but it didn't change anything. I did try run the game as admin but it didn't work.
I do not run any startup parameters and I never did.
When I played the game last time two or three weeks ago everything worked fine and now, without changing anything, the game takes 15 to 20 minutes to start.

Little update: When I leave the processes running the game does actually start after about 15 to 20 minutes.
I can play now but a 20min starting time is still an issue.