Can anybody do this ?

Imagine a file sitting on a network drive (this file could
be an Excel Workbook or a text CSV file). It can be
accessed by anybody in the business.

Often people will go into this file (not ReadOnly) which
causes a problem because somebody somewhere might want to
update or overwrite it completely.

I want a macro that will check the status of this file ,
by returning not Just the Excel Name of a user whose
inside it, but also their login ID.

I understand using a shared workbook is an option to
solving the above problem , but this isnt always possible.
I also have the API code for returning the login from a
local machine.

So how do I get the login of a user in a workbook/CSV file
on a network drive ?