I had that happen to me once when I was using my LTC-48161H to scan a Taiyo Yuden CD-R. Gave me a tracking error towards the end, C1/C2 went off the charts, and basically told me that the disc was unreadable. I didn't believe it because the disc read perfectly on my 451@851. So I rebooted my computer, and redid the scan using the LTC-48161H, and this time, it didn't have that problem and my TY disc ended up scanning just fine with less than 0.1 avg C1, which was more along the lines of what I had expected from my TYs. Moral of the story: sometimes, weird things can happen, and it might not be the fault of either the burner or the software or the disc.