Be VERY cautious about buying the larger-capacity USB drives, say 128 GB to 1 TB drives.   Unless you buy a few name-brands, like PNY, Sandisk, Samsung, it looks like the majority of the devices are fake.  What they do is to re-program the devices (which were probably weak or defective to begin with) to make it look like they have far more capacity than they really do.  If you try to write to them, at some point they will simply over-write the much-smaller capacity that they really have, which might be 4 or 16 Gigabytes

There are free programs which check these devices to see if they actually have the capacity they claim.   

            Jim Bell