This method work 100%, this how i usually set up my dual client. In order for this to work you
must go to your regedit and tweak a few stuff, do note that if you do this your maplestory client wont' work

. just reverse the method again and it will work. good luck hunting
2. Launch the Mabinogi Patcher
3. Press Start on the Patcher
4. Quickly Launch another Mabinogi Patcher
wait the the first done loading
Open Process Explorer
5. Go to Process Explorer
6. Press Ctrl+F
7. Type devcat into the box
8. Press Search
10. Right click on the highlighted text and click Close Handle
11. Scroll down or up (usually above the devcat line) a little, until you see some random characters (Or Korean if you had the language pack installed prior to Mabinogi)
12. Right click on it and click Close Handle
13. Close Process Explorer
14. Press Start on the second Mabinogi Patcher
15. Enjoy running two instances of Mabinogi at once!