Maybe...

http://contextures.com/xlfaqApp.html#AlreadyOpen
From Debra Dalgleish's site.

deniseh wrote:

When I initially open a file in Excel I am advised that a file is already
open The message is as follows: A document with the name 'ENTFUNCS.xla' is
already open. You cannot open two documents with the same name even if the
documents are in different folders. etc. This happens each time I open up
Excel with no other files open. Woukld someone explain what to do about
removing this message please, or how to get over this error?
Many thanks
Denise

--

Dave Peterson