alt+o | IRC| Logging --> click the button at the bottom marked "Logs and buffer saves folder"

or directly write to the mirc.ini

/writeini mirc.ini dirs logdir $sdir="Select directory to save logfiles in"

Make sure you know what you're doing tho.

DALnet #Helpdesk
I hear and I forget. I see and I remember. I do and I understand. -Confucius