Error code 3
This error indicates that your login request has timed out; if the issue persists, try using a VPN to connect to the game service. In case your login requests succeed when using one, consider calling your ISP for further assistance.
Error code 5
Usually, this error code is brought up when your Steam client is not ran with administrator permissions. Make sure to completely close it from the Task Manager and Windows Tray, and open it again by right clicking on the Steam Launcher icon and pressing "Run as administrator".
Error code 8
This error will be brought up when the game executable fails to be ran - this may be due to low system specifications or lack of administrator permissions when running the Steam client.
Error code 10
Error code 10 indicates that your Steam client has failed to initialize properly when Black Desert Online is launched. Make sure to completely close it from the Task Manager and Windows Tray, and open it again by right clicking on the Steam Launcher icon and pressing "Run as administrator".
Error code 11
This error occurs when you are attempting to start the game directly via the executable. Make sure to log into your Steam client, and start the game from your Library.
Error code 12
Your game client is not up to date. Make sure that all pending Black Desert Online downloads are finished, and if that doesn't remedy the situation, perform a Steam File Integrity check as described here.
Error code 901
This error will be brought up when a network related issue occurs - usually, it indicates that you are unable to properly contact the game server. Begin troubleshooting this error by temporarily using a VPN prior to opening the game Launcher; if you are able to connect to the game with the use of a VPN, consider contacting your ISP's customer support service for further assistance.