I am not aware of a way to limit excel to one instance. I did have to deal
with a similar problem and initially we tried using GetObject to get 'other'
excel instance, but it did not always work. We ended up using Windows API
calls to get processes and then check for excel.exe by.

If there's an elegant way to reliably do this then I am interested as well.
--
www.alignment-systems.com


"Robert Mulroney" wrote:


Is there a command line switch that will prevent Excel from opening multiple
instances of the application? I develop under excel and use an interface to a
thrid party middleware product. If the user opens multiple copies of Excel
then the middleware doesn't know which one to use and it's operations tend to
become unpredictable.

If there isn't a way to prevent multiple instances, how about a way to
detect it?

- Rm