I have used a lot of thumb drives in an environment with high risk of malware, and I never put one back into the laptop I rely on. So now I have all these exposed thumb drives. Is there a reasonable way to wipe them clean (no need to preserve any data) to make them safe to use?

Could I rely on Symantec Endpoint Protection to make it safe for me to insert them and delete them? Or is there some (relatively easy) other safe way? Or is it much safer to just toss them?

I bought them to be disposable, but there are so many I'd rather clean them if it is safe.

  • 1
    I think disabling Autoplay is enough to make the drives safe to plug in for formatting.
    – Seyren
    Commented Jul 29, 2016 at 7:54

3 Answers 3


You should first make sure you have backed up any all important files.

You should first Start up Disk Utility.

Plug in the thumb drive you’d like to reformat. It should also show up in the list of drives.In the screenshot you can see a list of the internal hard drive and DVD drive on my Mac. My No Name thumb drive is listed, and I’ve selected it in the list. Click on the thumbnail images in this post to see larger versions.

When you reformat a drive it completely erases everything that’s on it.

After selecting the thumb drive in the list click on the Erase tab on the right hand side of the window.

Choose a Volume Format from the pop-up — try Mac OS extended (Journaled), and if you wish, give the thumb drive disk a name.

Double check that you will be erasing the correct disk and then click the Erase… button.

After a few moments the disk is wiped clean. When I look at the disk in the Finder I see that no files remain. In my screenshot you can see the thumb drive now shows up in the left-hand column of Disk utility with the name I assigned it.


The absolute safest way is probably to get a machine that you can disconnect the internal hard drive on and boot from a Linux live DVD. Don't boot from USB, use a DVD.

That way you can reduce the risk of infection and by booting off a read-only media you know your formatting OS cannot be tampered with. It can be temporarily altered, but a reboot will always get you a clean boot.

In that live OS you should then be able to use standard Linux formatting tools. Depending on the flavour of Linux you may be able to disable automounting the USB as well and just format the device directly without even looking at the files.

Of course this assumes only "normal" malware. There is the potential for malware that is specifically targeted to rewrite the USB device firmware and the only guaranteed way to clean it then is probably in a high temperature furnace. I would expect malware of this type to be rare and extremely targeted as it would have to attack a specific device.

  • I don't think it would need a very high temperature furnace. Commented Jul 29, 2016 at 10:11

You can clean them by formatting.

Just before connecting them make sure that your pc does not do any action when a usb drive is connected, so it can just format them without reading anything.

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