I also have a Late '09 iMac and Blackbird, and found Mackie lagging behind on driver support back when I was running OS X 10.7.but the 4.0 drivers solved everything and it was running beautifully.and I have no excuse (other than stupidity) for rushing into Yosemite. Its only been a day or so, and i opened a ticket with Mackie about it, so i hope there is a fix soon.īottom line: Mackie Onyx Blackbird does not play well at the moment with Yosemite. Now the iMac 'sees' the Onyx, but the Onyx will not work - it does not 'see' the iMac back. I researched online to see if there were any known issues and i found none, so i (probably hastily) took the plunge. I use a Firewire-based interface with my 27' iMac (2010) - the Mackie Onyx Blackbird.