Just preparing for SL and have noticed from disk utility that I have 1 partition on my HD and it is mapped as MBR. How it got to be MBR, I have no idea. I don't know where I read it, but I remember seeing somewhere that SL can't be installed on to a MBR partition, unlike leopard, and it needs GUID. 1. This is correct? MBR is a no-go? 2. What options do I have to convert to GUID? I have backed up HD to TM & superduped to an external just in case. The internal drive is 320GB HD with only 15GB free. I was hoping to do a simple upgrade!