Can't import .m4r file into iTunes 10.0.6.40
Hi. I have a new iPhone 4S with AT&T (first iPhone ever!) and I'd like to create a custom ringtone. I have an .m4r file that is 29 sec long. I'd like to use it as my ringtone. Should be easy enough, right? I've tried dragging and dropping my file into iTunes, and also tried importing it through the menu, but it won't import. I can double click on it and play it in iTunes, but it doesn't import it into the library. Also, I have no RingTones folder. Do I need to create one somehow, and how would that work?
Thanks!
iPhone 4S, Windows 7