Game minimizes by itself, firstly when launched, secondly when alt-tabbed back. After several attempts to alt-tab back I finally managed to get into the game. Otherwise, it just keeps minimizing itself 1-2 seconds after I alt-tab back.
I updated videocard drivers, didn't help. Switiching to borderless seems to help but it yield much lower fps rate. It started happening after I uninstalled and installed the game. I have no new software which could interrupt other programs (all I have was there before and this did not happen).
{F27619}