NAS self delete exported img files from a user

[Bgnas]

We have NAS in our company and one user reported that when export img file from pdf into shared folder in NAS server, immediately the file is missing. I test also and i see the file until i refresh windows explorer. This occur only in one computer.
What could be the issue? Where to check?

 

[Ericloewe]

That's an awfully vague description, but permissions come to mind as a possible source of your problem.