Ian
Did you get this fixed?
My 2010 Outback has just developed something similar. After 15-30 minutes of driving the Map screen goes blank save for a message asking to insert a map DVD or that the DVD is not a map disc.
I've tried:
Ejecting and reinserting the disc
Inserting one of the other discs
Pressing the tiny reset button
My dealer suggested trying to identify what make of system it is - Kenwood / Pioneer etc. and doing some internet research, but I can't see how to find out what unit it is.
Anyone help?
Ewan