The most common cause of this is corrupt files in the user directory or missing prerequisite files.
Some players may experience issues with receiving drops in game if they have security software such as an antivirus or firewall blocking the game.
If your perks have appeared to reset to 0 completely, it is likely that your game client is having trouble reaching the Steam backend where your stats are saved.
Please check for missing components if your game will not launch!
Be sure to link your existing accounts!
This article will be updated regularly! Check for issues with connecting or matchmaking.