I'm not sure if I'm just not asking Google properly or what, but I can't come up with a good answer to this problem.
We have MDT 2010 setup and have a Task Sequence for refreshing Windows XP machines. It doesn't seem to happen all the time, but a lot of the time when we start a refresh it goes through the normal motions and when it gets into the first part of Windows XP setup (the blue screen) it stops, telling me a Windows installation already exists at that location and I can press L to continue, erasing everything and using that folder.
I've poured over the unattend file and can't find an option that will just delete the old files and keep going, so I'm at a loss. Any ideas?
I believe what you are looking for is a combination of 'AutoPartition=1' and 'UnattendMode=FullUnattended'. I'm not familiar with MDT 2010 but the answer file is pretty standard across all of the applications that use it.
http://unattended.msfn.org/unattended.xp/view/web/19/
The behavior appears to be somewhat based on how the client's disk is partitioned. I haven't done any extensive testing, but from what I recall if the target disk only has one partition (no OEM partition) then setup gets hung up at that point. I'm not really sure what the cause is (or if this is even the real problem) but it's the only thing I've noticed in my digging around.