After a while, I wanted to play Diablo 4 again, it updated upon launch and I clicked on some ad.
During the game a window appeared that I can’t click on, close, switch to, or dismiss.
It is something account window, that ask email and password.
I upload image, but i can’t it link here.
Any idea? Somebody can help me?
Have re-starded you’r computer ?
yes, many times
and checked the tasmanager too
Have you “scan and repair” ?
Un-install game and install it again ?
Un-install b-net app and install it ?
I found it! 
That was a third party application:
Crimson Market Compendium
I uninstalled and now everything is fine!
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Glad you found it, happy hunting 
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