1. What OS are you using ?
2. What software are you using for burning ?
3. Have you enabled DMA in your OS to help prevent this problem ?
4. What media are you using ?
Ok normally when the unit is burning the LED light should turn RED, well perhaps not on all, but it does on my BENQ and Liteon CD burners. If the LED light goes orange/yellow then this means that buffer underun has kicked in, and this will normally slow down the burn, or the burner will pause the disc while fixing up the error before carying on burning, really no big deal, but the burn will just take longer. When the % graph or mark (in Nero) goes below 50%, then buffer underun will kick in. I had this same problem with my Liteon 48246S and did burn or copy a CD at high speed (32x), got lots of orange lights and red. After some great help and advice from this forum, I enabled DMA in both my OS's Wim 2000 Pro and 98SE, and since then I've never ever had another orange light or buffer underun error.