So I have an external Lacie DVD burner, which supports DL at write speeds of 4X, if my memory serves. So I plug it into my new Macbook, put in a Memorex 2.4x DL disc, and use Finder to burn a folder. It seems to work fine, and the Leopard verifies it, everything fine there too. So I take the newly burnt disc out and insert it into the internal Combo drive, and nothing. Just hums for about 20 seconds, then ejects it. Any ideas? I thought perhaps it was the write speed, and I tried to set it at 1x, but couldn't go any lower than 2.4x when I selected the drop down menu. Why would it verify the disc if it didn't burn correctly?