Reference number: CH001171

Unable to read USB thumb drive.

Question:

Unable to read USB thumb drive.

Causes:

This issue could be caused by any of the following reasons.

1. Bad or not properly configured USB port.
2. Older computer with older USB support.
3. Bad USB thumb drive.

Answer:

Bad USB port

Quickly verify if it's your computer or the USB thumb drive that won't read, by trying to see if the thumb drive works in another computer.

If another computer can read the USB thumb drive but, your computer is not able to, try the suggestions below.

1. Try a different USB port.
2. If you're connecting the thumb drive to a USB hub, try connecting it directly to the computer instead of the hub.

Older computer

Older computers that are using USB 1.0 may not be compatible with some thumb drives meant for USB 2.0. Make sure your computer has the latest version of USB, if this computer has never been able to read the thumb drive. Information about determining your USB version can be found on document CH000602.

PC vs. Mac thumb drive

There can be compatibility issues when attempting to read a PC formatted thumb drive in a Mac, and a Mac formatted thumb drive in a PC. If the Thumb drive is working in one computer but not the other it's likely it's been formatted using NTFS and therefore cannot be read on the Mac, or HFS and cannot be read on the Mac. In order to get both systems to read the drive we suggest formatting it as FAT32 or MS-DOS using the steps mentioned below.

Note: Formatting a drive will erase any of the contents of that drive. If you're able to read the data on the drive on a Mac / PC we suggest saving that data on the computer before formatting it.

Windows users - Format drive

1. Open My Computer
2. Right-click on the USB thumb drive icon.
3. Click Format.
4. In the Format Window select the format of either FAT or FAT32 and click Ok.

Mac users - Format drive

1. In the Disk Utility section for your drive format the drive as MS-DOS.

Bad USB thumb drive

If you've tried all of the above suggestions and the thumb drive cannot be read in multiple computers, it's likely that the USB thumb drive is bad and will need to be replaced. Any information on the drive that has not been backed up elsewhere is lost.

Additional information:

• See our thumb or jump drive dictionary definition for additional information about this term and related links,