What if the command system does not work

Hello,

I have a USB stick and all of my files seem to have disappeared. I have followed the command instructions to retrieve my files back , and it worked , the files appeared again , but there is one big file that is still missing and I do not know what could have happened with it or why it did not reappear like the other files.

Can you please assist. Thank you so much for your feedback.

Regards
Mariska