1º Extract Game Client in a folder
2º Run mu.exe or main.exe or mu_fast.exe
3º Click 'Connect' on mu.exe or choose the server named xtyling.net on mu_fast.exe and ... have a nice game :)

Plese,before download game - stop your antivirus program becouse some of them alert for false positive!
Add Game Folder to your Antivirus
If use Windows Defender : Click here

MuOnline TEST Account Account: nakata
Password: 123456