These errors can occur when GameGuard’s file authentication failed during the initialization stage. We recommend that you delete your GameGuard folder and then repair the game client before attempting to login again.
Delete GameGuard Folder
C:\Program Files (x86)\NCSOFT\LINEAGE2\system\GameGuard
Repair the Game Client
This can be done by clicking on the Scan File option at the bottom of the NCSOFT Game Launcher window.
Note: If you have the Launcher set to start the game automatically, you will have to run the launcher once, close the game or Alt+Tab out to the Launcher mini window and adjust the settings from the Settings button in the top right-hand corner of the windows. Once done you can restart the launcher and you should be able to run the File Repair.
If you continue to experience an issue, please contact Technical Support by logging in and submitting a ticket HERE