File with an .NFS extension contains a temporary NFS system type file – a copy of a file which has been opened by a network process or deleted, but other remote processes still has opened access to it. Such copies usually has .NFSX extensions, where X is a random symbol, which enables NFS protocol compliant files management.

In case of an error on the client’s side, who uses a temporary copy of an already deleted file and disconnects from the server, such file can remain on the server. This is why adequate scripts that clean disk of unused temporary NFS files are often created and initiated,. NFS protocol enables user to remotely access files and exchange them.