I have an old My Book hard drive and decided to plug it in to my Airport Extreme just to test it. I plugged it in and my iMac recognized it right off. I cleaned up the hard drive and deleted some old stuff. Sometime after that I rebooted the computer and now the iMac is not recognizing it. I moved it from the Air Port Extreme and plugged it directly to the iMac and it still didn't recognize it. I tried it on my Macbook Pro and it did recognize it. I'm not connected wirelessly on the iMac but I am on the Macbook pro. Should that matter? Any ideas?