How to remove virus or disinfect USB drives

The most common way for malware to spread via USB sticks is for a malicious program on one PC to infect the stick’s ‘autorun.inf’ file, which then passes the infection on to the next PC it is plugged into. Some antivirus (AV)programs scan any USB sticks as soon as they’re plugged in. Most paid-for AV programs do this, while free ones like Avast Free Antivirus may also do this. In Avast click Settings, Active Protection, then Customise under File System Shield and select ‘Scan when attaching’ to check that ‘Scan auto-run items when removable media is attached’ is ticked. If your AV doesn’t automatically scan USB drives, you could add a free standalone tool, such as Ninja Pendisk or Bitdefender’s USB Immunizer , which scans and cleans any USB sticks you plug in.

There are a couple of ways to protect the sticks themselves.If you only need to read or copy files off a USB stick when it’s attached to someone else’s PC, you could use one with a physical write-protect switch, though these tend to be more expensive – a 16GB Kanguru stick will cost you about £40. Alternatively, you could use a free tool like Panda USB Vaccine , to stop your drive becoming infected in the first place – simply insert your stick and click Vaccinate USB.