The following review written by one of the Software Informer contributors applies to version 2.8
As suggested by its name, USB Guardian can protect your computer from malware, including worms and viruses that can use your USB memory device for transmission. This AV program can be set to start along Windows and remain hidden in the System Tray to monitor infections running from connected USB devices.
The program allows you to disable the autorun feature, thus protecting your system from ill-intentioned programs that can start automatically after a USB device has been plugged into your PC. However, you can exclude CD-ROM autorun to keep it functional.
The program works by scanning the USB gadget and detecting potentially dangerous applications, which are immediately locked. Then, you can decide to delete some or all of them. Similarly, you can unlock given programs when you are sure they are not harmful.
Unfortunately, the application does not have an attractive interface. However, it is very easy to use. Most of the times it will work automatically independently of your actions. Moreover, you can access its main window from the System Tray. It is a pity that this program’s installer practically forces the user to install a browser toolbar and change their default search engine and home page.