A flash drive can fail to work for a number of reasons, and troubleshooting it requires checking the unit's contacts, ports, drivers and bandwidth. If the USB drive itself is faulty, then contact the manufacturer, as it can often replace the drive with a new unit with the required files.
The first thing to check when a flash drive is not working properly is the USB port. If the unit is a 2.0 flash drive, it requires a faster connection than that of a standard USB port. Most computers have to switched to 2.0 or even 3.0 ports, but older models still have the slower ports built into them.
Inspect the contacts on the flash drive itself. If the unit has corroded contacts, it will not be able to make a solid connection to the computer, resulting in it acting buggy. If the contacts are dirty, clean them off.
Another common problem that arises is issues with the driver software. Every piece of hardware that is used on a computer requires some form of software to properly operate. This type of software is referred to as a driver and is found in the USB drive itself. However, if the driver was accidentally deleted, the user will have to download it from the Internet so the drive can work on another computer.