I'm not impressed with the quality control of Lexar re this card reader. A couple of weeks ago I purchased one to use on a new Dell Vostro 3350 (Windows 7) with x2 USB3.0 ports.
The first card reader that turned up was faulty, the SD reading aspect wouldn't work at all, the CF was fine. A replacement was sent out in due course and this time it won't register on some PC's sometimes, often not appearing on the same machine after a reboot or eject. I have access to 3 PC' and 2 Macs around the office and have tried various configurations, but the fault seems quite random.
I'll now have to purchase a different brand/model.