OK, I find thread with solution. Problem with Ubi introvideo
To fix this, simply rename or delete the Ubisoft logo movie file located in your Steam directory: \Steam\steamapps\common\il-2 sturmovik cliffs of dover\parts\core\GUI (
http://www.oceanicwing.com/Forum/Mai...sg4231#msg4231)
Will try it when I get home.