>Good points. I'll try fixing these, but I'm wondering if this can cause the different behavior we're seeing?

ShellExecute is a rather temparamental interface that's driven through
DDE. It has a habit of locking up the DDE server from time to time -
once hung Explorer pretty much dies.

If you can get away without using ShellExecute by all means do it.
You'll get much more liable results.

To hide your app I think you can use a PIF file to run the window
minimized. It's been so long that I don't remember. If it's
a Win32 Console app the the /n parameters will also work - sometimes
these will also work on DOS files.

Regards,

+++ Rick ---