It is compulsory to format your USB Key regularly if you are frequently performing File transfer to one computer to another. Your computer can get infected with potential worms that affect your computer or vice-versa. Another plausible reason for formatting your USB portable device is that your USB Key is no more recognized as a removable disk.
How to format your USB Key?
To format your USB key:
1. You just have to plug-in the device to your computer and wait for your computer to detect the device.
2. Once detected, select "My Computer" and right-click on the icon designated for the USB.
3. Then choose the format and set the highest capacity as default.
4. For File system, choose FAT32 and click on Start as per below image.