protect your USB drives from autorun viruses Bitdefender USB Immunizer can protect your USB drives from being infected by viruses or malware that are automatically launched via the autorun.inf file when the drive is inserted. When you run the program, it detects any removable drives that are connected and allows you to immunize them with the click of a button. Bitdefender USB Immunizer actually places a dummy autorun.inf file on the drive. This dummy file cannot be deleted or overwritten. (The only way to delete the file is by formatting the drive or accessing it from a non-Windows system.) Since there can only be one autorun.inf file, the presence of the locked Bitdefender autorun.inf effectively prevents any autorun viruses to be launched from the drive. You can use USB Immunizer as needed, or configure it to constantly watch for newly inserted USB storage devices and immunize them on the fly.