The problem is relevant to the disk "allocation unit size".
When storing files on a disk, they are not stored based on the actual size of the files, but based on the "allocation unit size".
Thus, when the "same file" is stored on a disk with a “different allocation unit size", the occupied "disk space" could differ.
Take the following picture as an example, the disk "allocation unit size” is 1024KB"
![](../Support/FAQ/FAQPics/1(14).JPG)
Multiple files with the actual file size of 4KB are stored in the drive. Each 4KB file occupies a disk space of "allocation unit size = 1024KB" for storage.
The actual file size and the occupied disk space will have a 256 times difference (1024/4=256), as shown in the figure below.
![](../Support/FAQ/FAQPics/2(23).JPG)
Solution:
Before saving the files, please refer to the source file, set an appropriate "allocation unit size" and then format it.
![](../Support/FAQ/FAQPics/3(12).JPG)
Note: Formatting will delete all files inside the disk.
Please back up the files before proceeding with the formatting process.