GERNE DEUTSCH ANTWORTEN! HAB NUR KEINE LUST, DAS JETZT ZU ÜBERSETZEN. I got two new MacBook Air, MacOSX 10.9.5, (serial number of this one, which I'm writing on: C02N78JDG086) having USB ports 3.0. Both do not recognize my external HDs Western Digital "My Passport", which appear on all other Macs we have. WD answers: WD My Passport SN: WXB1A72D3155 WD My Passport SN: WXB1A72D1743 Both hard disks do have the newest firmware. WD My Passport are Plug-and-Play and don't need extra drivers. These WD hard disks are compatible with USB 3.0 and USB 2.0. Please contact Apple support service, because the disks are not the problem: So, what could I do? Both disks appear on our older MacBook Air, also on MacBook Pro of 2008, on our iMacs. They have terabytes of data, and we need that. Do I really have them to throw away or keep our older Macs to read them??