I have a 2011 MBP (2GHz), with a Seagate 1TB USB powered external hard-drive which is constantly backing up via. Time Machine. Just now, I got my iPhone sync cable and plugged it into the USB port on my MBP, and then I got the error message pop up saying that my external hard-drive was incorrectly removed and may be corrupt etc. I noticed my external hard drive was just flashing, meaning that it considered itself as 'ejected', but still detected the power supply. I found this slightly odd, as I didn't have my phone plugged into the other end of the cable, and yet, just the cable was still enough to stop the power supply to the hard drive. Anyone else experienced this, or has any suggestions?