I have recently come back from a tour around China. Looking for a high capacity memory card was one of the most exhausting tasks that I had (excluding the task of communicating in Chinese, of course). I’ve been in several big cities around the country. Among them are Beijing, X’ian, Chengdu, Kunming and others. As I’ve heard (but did not check for myself), it is worse around Hong Kong, Guangzhou and Shenzhen which are, by rumors, the main source for fake merchendise in China.

The price for a fake 8GB microSDHC SanDisk memory card was 200 RMB as of September-November 2008. These are not real SanDisk cards, but 4GB microSDHC cards loaded with a virus. The same goes for fake Kingston 8GB microSDHC memory cards.

When you plug these cards into your computer, there are two options: Either your anti-virus will detect the hidden autorun.inf file or not. In case of detection, the file will be erased by the anti-virus, but will re-create itself during the next insertion. It cannot be deleted since the manufacturer messed with the memory card’s controller. The main purpose of this virus is to conceal the true capacity of the card.

Avoid purchasing high capacity memory cards in China

There are a few thumb rules before buying a memory card from China:

1. As of November 2008, there were almost NO genuine microSDHC 8GB memory cards. Even if you did get a memory card with real capacity, it is most likely a fake one. Still, it might work. Avoid, by any means, buying the top-of-the-line memory card from local stores in China.

2. Most high-capacity memory cards sold in electronic malls are in open packages. In case the packaging is not securely sealed, the card is 99% fake or with a virus.

There are two techniques to conceal fake memory cards: The common technique is using a cheap fake SanDisk packaging. It looks smaller and different than a genuine one. You can actually open the packaging to get out the card because it is not sealed. If it looks suspicious, don’t buy it.

The second technique is to use a genuine SanDisk or Kingston packaging, replacing the original memory card with a fake one loaded with a virus. You will see a small cut made with a knife in the plastic. This is less common. I’ve been requested to pay more money for these kinds of cards (approx. 240-300RMB). As a thumb rule, if the packaging is open, don’t buy.

How to detect a fake capacity memory card

The best way to check for a false capacity memory card is the slowest way: Take a bunch of big files (e.g video files). Copy 8GB of files into the card. Next, copy them back into your hard-drive and check their integrity (see if they still work). To make this test more objective, copy the files back into a different computer to make sure they are not copied from a cache somewhere on your hard drive.

The virus can usually be detected by an updated anti-virus, but in China, many computers are already infected so it is difficult to see these files. The two files on the memory card are hidden. I could usually see them using an external file manager such as Total Commander.

autorun.inf (hidden Auto-Run file. Executes whenever the a card reader is inserted into a USB port)

filename.vbs (this filename has various names. This is a VB script)

Both files are in the root folder.

In order to see these files you need to set the computer so it will show hidden files, or as mentioned before, use an external file manager application that can do that.

Detecting a false capacity memory cards

It is not easy to know whether the 8GB microSDHC card that you just bought is actually a 4GB microSDHC card. Checking in DOS mode or in the Properties of the drive in Windows will show you a 8GB capacity card.

I have followed these steps to detect false capacity memory cards.

1. Format the memory card.

2. Disconnect the USB card reader.

3. Insert the card reader

4. Check for hidden autorun.inf

In case there still is a hidden autorun.inf after formatting, the card has most likely false capacity.

Take into account that it is possible the computer you are using is already infected. In case the computer is infected, it might infect the memory card, making you think it is the fault of the card. As mentioned before, the best way is to copy files into the card to verify its capacity.

On the bright side, in all of the stores where I bought false-capacity memory cards, the sellers looked surprised. Most of them do not realize they hold fake merchandise. I received a cash refund every time that happened. It is a huge waste of time, though.

It might come as a surprise to you, but memory cards are not cheap in most parts of China. Be careful and avoid unless it is absolutely necessary.