MS has code here that checks to see if any file is open:

http://support.microsoft.com/default...;EN-US;q138621
XL: Macro Code to Check Whether a File Is Already Open (Q138621)

And it's even called "IsFileOpen"

Luis wrote:

Hello.
I have a list of several files that i want to open in
write mode. It could happen that some of these files are
being allready opened in write mode by other users. How
can i test if the file is opened exclusively by another
user? And if so, is it possible to give a message with the
Excel username of that user?

Thanks

--

Dave Peterson