Here's the deal - Our MDM X4's are giving us "INVALID" screens during every fourth or fifth edit attempt - basically "refusing" to delete some sections.
Sony only has ONE TECHNICAL SUPPORT person handling the entire US market, and he cannot give us a reason nor solution for the problem. I've talked to others who have returned their units because of this same problem as well.
I think they (Sony) has rolled out these units before the bugs were all out of them... I've e-mailed Sony in attempt to get an answer from someone in engineering, but they did not respond.
Their tech support guy told me that "he hasn't had time" to check into the problem since he's the only support person in the country - not to mention that "I'm the only one with the problem..."
Anyway, if you are planning to get one of these things - BEWARE of the editing problems when attempting to delete a track - you likely won't be able to!
-Joe Hammer (email@example.com)