Hello everyone. I hope you can give me a hand with a little issue I´m having. I have a late 2009 iMac 27" i7. I replaced the Superdrive with an 850 EVO SSD (boot drive). Everything is working great so far. Great speed improvement and I managed to keep my Superdrive in an external USB enclosure. I left my original HD in place, but would like to format it completely to store files, music, etc. Even though I´m booted from the SSD, I can´t seem to be able to unmount it and format it clean. Forcing the unmount in terminal doesn´t work either. I just want a clean, empty drive... Any ideas?.. Thank you.