>Now the only question would be "Why the difference in where in the logon process I start the program?" I don't plan to pursue that question, but I am curious. I suppose the good thing is I learned how to use ProcMon to help troubleshoot the issue.

SWAG: the drive letter is not assigned when you start early, it is read somewhen from the registry or a subst batch file.
>
>While you didn't exactly solve the issue, I'll give you credit for more than a simple "help".

unplugging the power cord would have worked as well ;-))
was meant to safeguard against subst-ing earlier, possibly into sub-paths or via registry/controller assignments

>Thanks for the assist

resolving an issue for somebody actively helping along and with good ideas/instincts is even more of a pleasure.

regards

thomas