I have tried PNY USB Flash Drive and wors just fine. when I try to use SanDisk Cruzer Micro USB Flash Drive it will recognize the U3 section of the drive. Just to refresh the Cruzer Micro. it has two partition. One is U3 that contains portable apps which is read-only and other will be open partition. Paralles will recognize U3 in the USB bar at top. but if you choose , it will alert its been used my another application. Since I use mac most of the time , I found applcation to remove U3 partition and make it single one partition. it works.. plug in to usb ports and finds right away. This should be looked at it. SanDisk is selling with U3 portable app installed on most their flash drive that is Cruzer line..