Some jobs are locked to a specific OS (Linux or Windows), but some jobs "float" . . . the point is to test the build under both OS's. Thinking I was designating the location of the build from the master (where post build plugins generally run) I entered the Linux AFS path for my archive:
Imagine my surprise when after 18 minutes of copying the share was still empty.
I eventually found the copy at D:\prj\...
For jobs that don't float, this can be set to the "right" location, but for jobs that do float there is no right address for a network share that can be seen for both OSs.
Either you need to let the master resolve this (yes I understand the implications of copying 40K files that way) or else you need to allow for two paths . . . one used for Linux . . . one for Windows.