I am using Office 2003 on Windows XP.

Scenario: I have an Excel file uploaded into an Outlook folder. When users
open this file it automatically generates a form number on-open that uses the
date and time down to the second. All form numbers must be unique, but NOT
necessarily in sequence.

Question: Given the scenario above, is it possible for two or more users to
open this file at precisely the same moment and receive the same form number?
Or is that impossible? Would one or all get an error? Or is there some way
--- code wise --- to prevent that from happening? Remember, this is in an
Outlook folder which allows users to open a copy of the file - but not change
the original...

Thanks much for your assistance.