Android File Transfer on Mac not working with my Nexus 4

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http://forums.androidcentral.com – I just got my nexus 4 and when I try to plug it into my Mac and running Android File Transfer it keeps telling me " No Android device found" I tried with MTP mode and with PTP mode, I also turned on the debugging mode, and it still doesn't work. I also have a nexus 7 and when I plug this one to my Mac it works perfectly and I can transfer files without any problem, so I really have no idea what the problem is when it comes to my nexus 4, has anyone had a similar problem, or can anyone help me please? (HowTos)