My original DVD can no longer be read in the car - I worried that the navigation system just had a bad dvd reader, but I found I couldn't read the DVD in my computer either (and there are no scratches or fingerprints etc. on the DVD - it looks pristine). I got a new set of 2014-2015 disks and the good news is my nav system can read them. However I don't trust leaving these discs in the car or in the system (don't want them to end up unreadable like my previous disc).

I read "A LOT" of old posts here and elsewhere on how to make a backup copy -- lots of confusion in those posts with some people making copies that work and others following the same instructions and it not working. Lots of people speculating various copy protection schemes and special brand of writer required etc. -- but here is what I learned in the attempt:

My car is a 2004 which means it was built in 2003 - and that is about when double layer blank DVDs were just coming on the market (apparently double layer is in the original spec for DVD so even old readers can read double layer - but if I'm reading the history right, there were no double layer DVD media or writers until mid 2004).

Most posts talk about having a specific type writer and a specific brand/batch of blank DVDs ... I couldn't find any posts discussing various years of readers (in the car). But I did find many posts saying someone copied a DVD and the copy could be read in one car but not in another car.

Factory DL DVDs are more reflective than the writable DL DVD blanks.

My copies are readable on the computer and look to be just fine - but can't be read in the car. (Verbatim DVD +R DL) I wrote them in Booktype DVD-ROM and tried every other suggestion from many forum posts. Still couldn't read them in the car.

After reading up on the DVD spec and how writable DL DVDs are less reflective than factory DL DVDs, I started to suspect that my reader was just old enough that it couldn't make the fine laser adjustments needed to differentiate between the two layers of the writable disk but that it could manage with the factory DVD. I decided to test my theory by burning a single layer DVD and just setting it so that when it got to the end of the disk it would truncate the data (leave off a lot of the maps) ... and that disc read just fine in my car. It booted up and worked normally unless it needed to pull up a map that didn't exist on my disc.

This test told me that there is no copy protection or that sort of thing causing the copies to not be readable - it was just that my reader can't read these particular writable disks. It may well be that some other brand or batch of writable discs might work -- but I could spend a lot of time and money trying different brands of writable discs.

It would be interesting to see if a newer year Volvo would read my copies - I suspect it would.