got same issue recently.
Shrink can't read whole disc, about 30% error msg pops out.
try DVDclone or cloneDVD, about 50% is dead.
then alcohol, same, dead at 50%.
above were done by LG burner, forgot model.
then tried Pio 11 or 10 burner, it can't even read disc!
last hope is another burner, NEC, not sure which model. bingo, this one can backup that problem disc successfully!
