Well, I'm stumped. I downloaded the disk image of 10.1 last night, used Toast to burn a CD and it seems to be OK, but when the installer runs it tells me that it cannot be selected as a startup disk. I have tried starting up from CD (ie., holding down the C key), mounting the disk image on the desktop without the CD, starting up from my 10.0.3 disk with the upgrade CD in a USB CD drive, etc. I feel like I'm missing something very obvious but damned if I know what it is. Any help would be appreciated. I have tried this on both my 333 mHz iMac and my iceBook.