Bitdefender USB Immunizer - Version 2.0.1.8 Bitdefender USB Immunizer is a free and easy to use tool that helps make sure you transfer the files, not the viruses. It disables autorun-related threats before they access the computer. Once installed, it constantly watches for newly inserted USB storage devices and immunizes them on the fly.The Immunize option allows you to immunize your USB storage device or SD card against infections with autorun-based malware. Even if your storage device has been plugged into an infected computer, the piece of malware will be unable to create its autorun.inf file, thus annihilating any chance of auto-launching itself.