You have to change your file system from DOS. The process is very simple. And one more thing, This process will change file system without harming or deleting your files inside your flash drive. That’s mean your files will not be deleted. Just file system will be changed. Just follow the steps below:
2. Open DOS or Command Prompt. (Start->All Programs->Accessories->Command Prompt)
3. Command Prompt will be opened. Just Type “convert FLASHDRIVEPATH:/fs:ntfs” and press Enter.
The final command: convert l: /fs:ntfs
You can see in picture below.
wait for some time and file system will be changed.
Note: Just format the flash drive to get Fat32 file system back.