There are several reasons why the files in the USB flash drive may become empty:
1.Files are hidden: Sometimes, files may be hidden by a USB flash drive, at this time, you can check the properties of the USB flash drive in the computer, if the data shows that it takes up space, but the file cannot be found, then they may be hidden.
2.File Deletion: Files may be deleted due to various reasons such as misoperation, virus attack, etc. In this case, stop writing new data immediately to prevent new data from overwriting the deleted file.
3.Physical damage to the USB flash drive: The main controller or memory chip of the USB flash drive is damaged, which may also lead to the loss of files. In this case, the possibility of file recovery is relatively small.
4.Software Corruption: There are necrotic sectors inside the USB flash drive and some files may happen to be stored in these sectors, thus leading to file loss.
5.Editing errors: During the process of editing or copying files, if the USB flash drive is pulled out before the file is fully executed, the file may also be lost.
6.Computer Viruses: USB flash drives can be infected with data viruses that can also lead to file loss.
To protect data security, it is recommended to regularly back up important data in the USB flash drive to prevent data loss. If you lose files from USB flash drive, you can try to use data recovery software or seek the help of a professional to recover the data. However, please note that recovering data on your own is not always successful, and there are certain risks in the process, so please be cautious. If the data is very important, it is advisable to contact a professional body directly for processing.