I have an IMac too. Well, about your problem, can't you just go to Tools in the control panel at the top of Limewire, select Options, then Saving on the left side at the top.....then you can chose the library. Do you have Itunes? If you do, you want to save the music files to the Itunes folder that is inside of the Documents folder, not the Itunes folder in the Application folder. Does that make sense? Well, if you need further assistance, you can email me at **Edit** because I think I know my IMac pretty well.