Lately I've been getting the windows10 sound called Asterik everytime I press a key when I'm on track. I thought it was one of the utils I was using like Crew Chief, but I just loaded the sim to test the engine start json setting and the Blinngg! was still there. Power up the car, Blinnng! Hit the starter motor key...Blingg! What have I done to get windows stuff inside the game? On the menus, probably because I only use the mouse, I don't hear those sfx. Only in the car on track.
You need to alt-tab, your problem is probably related to the common issue of the game not really running in fullscreen on first launch.
It happens sometimes also for me, Win 8.1. I'm not sure but i think it has a correlation with the mouse scroll wheel when it don't want to work in the main menu. @stonec i'm using borderless mode
Happens to me also, I've just had to get in a habit of Alt-Entering to make it fullscreen. I tend to alt-tab as well and if OBS shows the screen preview I know I'm okay (as it's set to record only a full screen app)