Hi there, long time lurker first time poster here, I am having a problem - I have upgraded my trusty old A1211 Macbook Pro with a new drive. Everything is working superb, a fresh installation of Lion is installed on my new drive - already installed inside my macbook. The thing is I have removed my old drive (used for years with software, settings, libraries and whatnot) and installed it inside a USB case. The disk is detected correctly works great BUT it will not allow me to boot from USB into my old installation of OSX 10.5.8 Leopard that is still UNTOUCHED on my old external drive. It will boot ok as 10.5.8 when installed inside my macbook but it will NOT allow me to boot into 10.5.8 when it is inside my USB enclosure. I have tried installing it inside my FIREWIRE enclosure and it still will NOT boot into 10.5.8. From what I have read - 10.5.8 does not have a file that would allow it to boot from either USB or FIREWIRE - is that the case ? The drive is correctly detected, it is accessible I can access the files copy / delete / move them - but it REFUSES to boot into my old system ... I tried partitioning my new drive - I created a partition the size of my old drive and intended to use CARBON COPY CLONER to clone my old HDD with 10.5.8 and make it a secondary partition on my new drive - I wanted to clone the data from my old drive into the new one - and be able to boot my machine INTO my 10.5.8 OS X installation (leaving my Lion partition intact and ready to be used when needed). After selecting my SOURCE partition (old HDD with 10.5.8) and selecting my DESTINATION partition - CCC displays a message saying "warning, the resulting partition will not be bootable - the source drive is missing a mach_kernel file) Any ideas how I could boot into my old 10.5.8 system - without removing and installing the disk as a primary internal drive ? Just to clarify: I have my new drive with Lion inside my macbook I start themachine press OPTION key - and have all drives listed I select my OLD drive with 10.5.8 hit enter and for a fraction of a second it displays a crossed circle (like this one http://www.clker.com/cliparts/Z/Z/S/Y/S/w/red-circle-cross-transparent-background-md.png Then it proceeds to boot inside lion using my new drive instaled inside my machine.