There are two types of problem U-disks: expansion disks and fake U-disks

First, what is the meaning of expansion disks? For example, if you buy an 8G U-disk, its properties are 8G on the computer, but it is actually a fake chip with 2G or even smaller memory, which is expanded by software. Once you load something that exceeds its actual capacity (2G), all the data you loaded will be scrapped and cannot be read. Think about it. If you have important documents in it and don't back them up, the loss will be irreparable.

second, the so-called fake USB flash drive is made of chips produced by some small manufacturers, and branded on the outside, which has turned into a famous brand. Although the capacity of this kind of USB flash drive is sufficient, the quality is extremely unstable and cannot be guaranteed, and there are many problems. If you accidentally and inexplicably, the whole disk becomes a waste disk, and the files inside cannot be recovered at all.

3. Ways to distinguish whether a USB flash drive is genuine or defective:

1. Use software tools to detect whether a USB flash drive is an expansion disk! Software tools, such as MyDiskTest, plug in the USB flash drive and then open the software, which will be known as soon as it is detected. However, as the saying goes, the magic height is 1 feet. While the testing software tools are constantly improving, the expansion technology is also constantly upgrading, so it is really impossible for professionals who do not often use such tools to identify them. Ordinary consumers are easily fooled.

2. Use files to detect, which is the simplest and most effective method for the expansion disk. Both mobile phones and computers can be operated. The step is to directly import a file with a size of 1G (for example, for a disk with a capacity of more than 1G) into the disk, and then copy and paste the file in the disk continuously, and then constantly observe whether the thumbnail of the newly pasted file is abnormal, and see if the file can be opened normally when it exceeds half of the nominal capacity or if any thumbnail is abnormal. Repeatedly, if the file is damaged, it is an expansion disk.

3. Look at the reading and writing speed. The writing speed of 8G is more than 4MB per second, the reading speed is more than 14MB per second, and the speed of 16-32G is doubled by adding 4MB on the basis of 8 G.

4. Don't buy the price that is too low. Besides professional quotation websites, the best way to make a normal quotation is to look at the quotations from JD.COM and Tmall.

5. Look at the packaging. The genuine packaging is clearly printed and has anti-counterfeiting code.

6. Whether it's a USB flash drive or an SD card, you must explain to the store that once the quality problem is found, the store must bear the transportation fee or replace it with a genuine one. Also, remember to buy transportation insurance.

In fact, it is a little difficult for non-professionals to distinguish genuine products from fake products, and there are so many fake products on the Internet. If your documents are important, be careful.