I have a Verbatim flash drive that won't mount on my iMac, it's running latest version of Lion and is a 2011 TB entry level iMac. The drive worked with the iMac when I got it but now nothing happens when I plug it in. I've tried it with a USB hub and plugged in directly and tried Disc Utility and System Information. the drive does work with a XP laptop and a 12" Powerbook. Any suggestions for getting it to work again?