How to Format and Safely Dispose of Old USB Drives, According to Engadget

Formatting a drive does more than remove visible files. It overwrites sectors so previously stored data cannot be easily recovered, sets up a fresh file system and scans for bad sectors. Engadget recommends formatting a USB drive before reusing it, even after all files have been deleted, because the process clears hidden ghost files and potential malware and optimizes stability. It also recommends formatting a brand-new drive before first use, since many flash drives ship with FAT32, an older format that cannot handle files larger than 4GB.

Windows users have three main file-system options when formatting an external drive. NTFS is best if the drive will be used only with Windows because it supports partitioning and encryption. exFAT offers the broadest compatibility outside Windows, handles files larger than 4GB, and works with Android phones, Linux computers, Macs and iPhones. FAT32 has the widest compatibility with older devices such as car stereos and older printers, but it cannot store files above 4GB and is more prone to fragmentation.

The Windows formatting tool is straightforward. Plug the drive into a high-speed USB port, open Windows Explorer, click This PC, right-click the drive and select Format. Choose exFAT for cross-device use or NTFS for Windows-only use. Leave file allocation at the default unless the drive is intended for very large files, in which case a larger allocation size can be selected, or for many small files, where a smaller size is preferable. Enter a volume label if desired, click Format and confirm. The process can take from seconds to minutes depending on drive size and fullness.

Simply deleting files does not remove them. It only marks the occupied space as available for new data, and recovery software can still restore the deleted files. A full format, which scans for bad sectors and overwrites existing data, makes recovery much more difficult, while a quick format does not. The Windows formatting tool includes a Quick Format option that should be left unchecked when a thorough wipe is needed.

For Mac users, Engadget says the built-in Disk Utility can erase connected drives. Open Finder, go to Applications > Utilities, launch Disk Utility, select the drive and click Erase. For some storage types, macOS offers Security Options that let users choose how many times the drive is overwritten. After confirmation, the erase takes time to complete.

A full format cannot guarantee data is unrecoverable. For sensitive information, physical destruction is the safest option. Physical destruction is especially helpful if the drive is not recognized by a computer, making it impossible to wipe. Cornell University's IT security guidance recommends overwriting functional drives three times before recycling and physically destroying drives that are disposed of. Mechanical hard drives can be disabled by hammering a nail through the casing to damage the platters. For SSDs and flash drives, iFixit recommends opening the enclosure and using a chisel, Dremel or drill to damage each memory chip. Care should be taken because breaking drives can send sharp metal and fiberglass fragments flying.

After the drive is wiped and destroyed, it can be taken to an electronics retailer that accepts old gadgets or to a designated e-waste recycling facility.