When you’re looking to dispose of old electronic devices, recycling them is the best course of action to take, however there are a few checkboxes you will want to complete before doing so. The first is to make sure that the device you are looking to get rid of no longer contains your personal information. For instance, when it’s time to donate or ditch an old flash-memory drive that once stored sensitive information, because simply deleting your old files won’t cut it. In fact, the safest way to wipe the slate clean is to actually encrypt the device as strange as that may sound, which is much easier than it sounds.
The computer industry’s migration from hard drives to flash drives has mostly brought about good things. Flash drives work faster and since they store data in solid-state memory, they also work longer. They’re also a lot smaller. If you’re not sure if your external drive is flash or not, seeing if it fits cleanly into a shirt pocket should be your biggest clue, followed by its complete absence of noise.
But when it’s time to wipe the drive so you can either sell or donate it to someone else, flash drives can impose quite a few complications that hard drives don’t. The first being that because they automatically move bits of data to less-used areas of the drive to extend longevity, the traditional secure-erase technique of overwriting files with random data may not clear out all of it.
Which was the driving force behind why Apple removed the “Secure Empty Trash” command from the macOS Finder in 2015’s El Capitan version. The tech giant didn’t want users to mistakenly think that they could scrub a file from a drive when the attempt might not succeed on a flash drive. However, users are still able to use the method of dumping random data three times in a row on an entire flash drive although tools to do that are less than obvious in both Windows 10 and macOS High Sierra.
For users with a PC, in the command prompt found on the Start Menu, type in “format e: /p:3,” (note: you will need to change the ‘e’ if the letter does not correspond with the letter for the flash drive). Whereas on a Mac, users will need to open the Disk Utility app, select the drive, click “Erase,” then click “Security Options…” and move the slider control to the third, “3-pass secure erase” option.
Mike Cobb, director of engineering at the data-recovery firm DriveSavers, noted that your flash drive’s vendor may provide an app with simpler secure-erase tools, pointing to ones from Intel, SanDisk and Samsung.
However, another reason why you may want to avoid this method is that it can be somewhat painfully slow on larger drives. To put this in perspective, a 2017-vintage Windows laptop would take about 22 minutes to do a triple overwrite of a 4 GB flash drive.
In fact, encrypting the entire drive to make its contents unreadable without a key — then erasing it and encrypting it again — takes much less time to make your data disappear. Both Cobb and Joseph Lorenzo Hall, chief technologist for the Center for Democracy & Technology, endorsed that strategy.
To do this on a Mac, simply right-click the drive you want to wipe and select “Encrypt” and then follow its prompts. If you don’t see that prompt, it may be because the drive was formatted for use with Windows systems; open Disk Utility, select that drive, click “erase” and go with the default settings. Either way, you’d then use Disk Utility to erase the drive, then repeat the encryption step. Finally, erase it in Disk Utility again to leave it free for the next user.
Things are a little more complicated in Windows, thanks to Microsoft not supporting disk encryption in the Home editions of Windows. (Dear Microsoft: Home users care about privacy too.) If you run a home version of Windows, you’ll have to use the open-source VeraCrypt app for this task.
Install and run it, then click “Create Volume” and then “Encrypt a non-system partition/drive.” Choose “Standard VeraCrypt volume,” click “Select Device” and then “Removable Disk”–where you should only see one drive selected, assuming you unplugged other external drives first.
After encrypting the drive, reformat it (right-click it on the Windows desktop and choose “Format…”), then repeat the encryption step. Reformat it a second time so the next user doesn’t get a prompt to decrypt it.
This is a bit more work than taking a crowbar to a dead hard drive. But learning how to encrypt drives — a must if there’s any risk of somebody stealing your computer — is worth going to that trouble.