I have bought several MKIV nav computers for a number of upgrade projects, both brand new and from eBay. They all have problems reading copied DVDs. So, do not feel bad, like you may have purchased a defective unit. This is 100% normal for most people's experiences. I would go out on a limb and say that anyone who gets a MKIV to read a copied disk cleanly all of the time is probably more the exception than the norm.

Like ccfj1 says, if you burn a backup copy at a slow speed, and use very good media, you can make it better. But I'll bet you still see regular crashes. I had pretty good look with Verbatim media on mine.

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SOLD
2000 E38 750iL Highline Edition, Upgraded with the lastest 2006 X5 Electronics
MKIV Navigation, 16:9 Display, Bluetooth, TV/Video with Backup Camera, Sirius, and Aux Input