Why does my Mac computer USB can not be detected?
Mac computer operating system 9.0 or higher system does not require special drivers to detect the USB flash drive.

If the USB mass storage driver is modified or deleted then the USB flash drive can not be detected. Remove all USB devices from the system, to Apple's Web site to download and install the USB driver.

Try the USB flash drive directly into a Mac computer, rather than put it into the USB port on the keyboard.