Folks I'm new here so bear with me.
I had a relative contact me today with the problem of a ITunes DEP issue with on a Vista machine,
I've spent the whole day on this and confirm that stripping everything out of Vista to do with Apple products including Registry settings and re installing ITunes following the guidelines did work...however the user still gets the DEP message on closure of the Itunes program.
My important observation though is I created another normal user for myself and when I open and close Vista I don't get the DEP error on shutdown.....I since found out that my relative is administrator for the machine, which indicates his rights is allowing him to do something DEP doesn't like.
I suspect that the excessive rights is or could be the issue which begs the question what would an administrator account be doing that a normal user wouldn't, interesting though.
If I learn any more I'll let you know
Earlonics