Hi guys, I'm REALLY hoping somebody here can help me, as I've been all over trying to get this figured out. For starters, I'm using Mid-2012 15" Macbook Pro (non-retina)--2.3GHz I7. 16GB RAM-- OS 10.10. 500gb HDD. Record to LaCie 7200RPM USB 3.0 External and on Logic 10.1. Kontakt, Massive, etc, were all working fine. Then, I went to open a new track with Kontakt and started getting this loud, rhythmic noise/crackle/etc. I tried a track with Massive, FM8, Reaktor--same result. I opened a brand new session, tried the same things--same noise. In fact, when I open these guys, they seem to almost overload, in a feedback-y kind of way. More like a hum. Opened the same instruments in Pro Tools 11 and everything worked smoothly--no crackle/noise. Any idea why this would happen out of nowhere? The only change I've made is that I set Logic up to send Midi Time Clock info from my interface (Roland Octacapture). I've turned that off, though. For what it's worth, my midi controller is a Novation LaunchKey 49. I also noticed that the Logic arpeggiator failed to work after arpeggiating 2 notes (as soon as I turn it off, the Logic instrument will typically work fine). Although, after trying Massive again today and getting the same noise buildup, I switched to the built-in Logic el. piano and it became noisy as well. I'm pulling my hair out here, as everything was fine until I messed with Midi Time Clock. I tried updating from OS 10.9 to 10.10 (Yosemite)--nothing. Any ideas on how to get rid of this noise situation?