@uliwooly thank you for your response. Yes, it happens even after restarting an app, recently even after reseting whole phone. In such apps I've got black screen and in Camera app it says that camera is unavailable.
@CameronT thank you for your response. I've cleared data from Camera and forced it to stop. The problem still occurs. Forcing app which does not work to stop does not help either. As you told, I've gone to the safe mode and I was also unable to go to the Camera app. There was a black screen, saying that Camera is unavailable. Forcing stop did not help too.
