If your USB drive cannot be formatted and is informed with a prompt “ Window was unable to complete the format ” error, it indicates that windows can’t format USB drive, and the USB flash drive is inaccessible. This post will give solution s to this issue. USB drives are very portable, and they can be connected to a computer easily via USB drive to backup or transfer data, which have become an essential component in various digital products such as digital cameras, cell phones, MP3 players, etc. Since they are often carried by users and might be used on various computers, USB drives are more likely to get many problems. For example, you plugged your USB drive into the port of a PC, right-click the disk icon and select “Format”, but it popped up an error saying “Windows was unable to complete the format”. So, does that mean your USB drive is broken? NO! This error may happen as a result of the following reasons: The Main Cause that Windows can’t Fo...