The box said Toshiba Canvio, and the sticker on the drive matched. It promised 20TB of portable storage for £38, about $51. When it was plugged in, Windows saw a 19TB disk and mounted it without complaint.

Then the trouble started. The drive froze. Files copied onto it showed up in the folder but would not open. “My dad brought me a new 20TB HDD and asked me to find out what the problem was,” his son, Martin, wrote in a Reddit post.

“The file could not be opened, no matter how hard I tried, including reformatting the hard disc,” Martin told Ars Technica. So he opened the case. Inside the black plastic shell there were no spinning platters and no read heads. There were two steel wheel weights, the kind used to balance car tires, glued in place, and a small circuit board with a USB connector.

A 19TB Reading That Gave the Game Away

The first clue was on the screen. Drive makers count a terabyte as a trillion bytes, but Windows measures in tebibytes, a unit about 10% larger. A genuine 20TB drive therefore shows up in Windows as roughly 18.2TB. A drive reporting 19TB was claiming more space than a real one of its size could.

That number came from the little circuit board, not from any disk. Fake drives of this kind carry a small amount of flash memory, the same type of chip found in a thumb drive, and firmware that tells the computer it is far larger.

According to Steve Gibson, a software developer who builds tools to catch these devices, the real storage is often around 64GB, enough to hold the folder listing. Files written beyond that point appear to save normally, but their contents are thrown away. The drives “silently discard any data written where there’s no storage,” he writes, and the first sign of trouble is usually a file that opens empty.

Heft From the Tire Shop

The wheel weights appear to have been there for heft. A portable hard drive has a recognizable weight in the hand, and a shell holding nothing but a tiny board would feel suspiciously light, so the steel made the fake feel like the real thing when the box was picked up.

The branding did not hold up either. Toshiba’s Canvio portable line tops out at 4TB, the capacity it added in December 2018. There has never been a 20TB Canvio.

Martin’s father had bought the drive from UK.Chicntech, an online shop whose catalog is mostly car accessories, kitchen supplies and home textiles. Ars Technica was blunt about it. “We do not recommend buying from this website,” the outlet wrote, adding that the shop’s “return and exchange policy is full of confusing and unclear wording, which is a red flag in itself.”

A 30% Refund and a Free Gift

Getting money back proved harder than finding the weights. According to Martin, the seller’s support staff first refused a refund and kept asking him for information he had already sent. At one point, he said, they claimed the weights did not affect the drive’s performance.

The shop’s final offer was a refund of 30% of the price, plus a “free gift” redeemable at the UK version of another online store, cacogoga. Ars Technica found no obvious link between the two sites and contacted both. Neither replied. Martin’s father turned to his credit card company instead, seeking a chargeback to reverse the payment.

Twelve Thumb Drives, Twelve Fakes

The trick is not new, and it is not limited to hard drives. In September 2023, Gibson bought 12 inexpensive 1TB and 2TB thumb drives on Amazon to test a free program he was writing, called ValiDrive. It writes test data at random spots across a drive’s claimed capacity and checks whether it can read it back. “Every one of them was a bogus fraudulent drive,” he reported. One sold as 2TB held just 62GB of real storage.

When the drive was first connected, it appeared on the desktop under a name written in Mandarin. “The device appeared to mount on the desktop with the device name in Mandarin,” Martin said. Translated, the name simply read “Hard Disc.”