diskpart.exe 'clean' command hangs

[Dan]

I'm running diskpart.exe from inside XPE. I'm then
issuing the 'clean' command after one of the physical
drives is selected.

It just sits there forever, but if I Ctrl-C out of it, go
back into diskpart, and detail the disk, I notice that it
actually did the work, but just never returned from the
call.

Anyone have an idea how to get around this?

Thanks,
Dan