Turning on compatibility mode
Compatibility mode allows older games to run on newer versions of Windows. Whilst this is not necessary for RuneScape or Old School if you're having problems with the game loading properly or receiving the error code c0000409 try turning Compatibility mode on.
Turn off Compatibility mode
- Right-click the RuneScape launcher
- Select 'Properties'
- Hit the 'Compatibility' tab
- Under 'Compatibility mode' check 'Run this program in compatibility mode'