No need to mess with U3. I eliminated it from my flash drive. You should just be able to copy files onto the drive. It will show up as a separate volume in "my computer", and then you just copy and paste onto it.
I have read that if you remove the U3 software from the San Disk Cruzer flash drive it slows down the write speed, can anyone confirm this?
I don’t know why you are having trouble using the flash drive you just use it as you would any other removable drive remembering to use the safely remove hardware icon.
One problem with this drive (and all very fast flash drives) is that it draws to much current for an unpowered hub causing unreliability if you were to try to do so.