Client CRASH ON LOADING Thread - Post here, DO NOT create other threads

I welcome everyone. At me the customer is already acting correctly. However from time to time while loading the window is disappearing. At first I restarted computer and it helped. However once by accident I have noticed that the customer is involved. Indeed he is disappearing from the desktop, but it turns out that they are simply minimizing it will be sufficient to press F12 and the window of the game appears. Perhaps it will help somebody. I am greeting