method One:
1, the U disk inserted into the computer, open My Computer, right click on the disk of the U disk character, select attributes;
2, as shown in the picture, the display is a 4G u disk (shown as 3.9G is normal, because the hardware itself will occupy part of the capacity);
3, in this U disk to create a new name for the "movie" folder, and copy the video file into this folder;
4, after the completion of the copy, view the file or U disk properties, the size of the diagram is 1.62GB (no more than 3GB);
5, click the Eject U disk (this process is very important);
6, plug in the U disk, and open, found that the contents of the movie folder disappeared;
7, but open U disk properties, the display capacity is still occupied by 1.62GB, also available 2.28GB, indicating that the U disk is a shrinking disk.
Method Two: Use antivirus software to detect
1, open Jinshan poison PA (or other software), select "Visionary", click on "U Disk Guardian";
2, click on the "Capacity identification" testing the real capacity of U disk;
3, the identification results show that the U disk is indeed a Shrink U disk, its display size is 4002MB, the actual only 975MB (is 1GB capacity).
On the computer to test whether the disk is a shrinking disk of the two methods introduced to this, in the purchase of U disk when you have to be careful not to buy a shrink u disk.