Hi all, Yesterday, I decided I would try and boot my MacBook Pro from a USB Key with a version of Linux on it. I have no particular reason to use Linux and it's been about 10 years since I installed in on anything but I thought I would give it a go and see what I could learn. So I inserted my USB Key, rebooted the MacBook and held the Option key down while it booted and it loaded the Startup Manager. To my disappointment the USB key did not show up, so I re-inserted in a few times but still nothing. It did of course show the internal HDD with an icon under it. While playing around I accidentally pressed the Control key and the icon under the HDD changed, so I clicked it. Nothing happened. Close to giving up, I rebooted the MacBook to return to Mac OS but it wouldn't boot, even after several tries. At this point my hard rate had increased about 10 times because it's been a week since I did a backup and I have done a LOT of work on it since then. Stupid I know. I trawled the internet hoping for a simple solution. I found plenty of advice about booting to Single User Mode and copying the files to an external disk, which I tried but only knowing the very basics of Linux I couldn't make it work. I followed the instructions on repairing the 'invalid sibling link' and 'catalog errors' to no avail. I tried booting with the Mac OS X install disk and using the disk utility but the Repair Disk option wasn't available. I tried creating an image of my damaged HDD on to an external drive with disk utility (which I left running all night incidentally) but it didn't work. I tried copying the files in Terminal session but again, couldn't make it work. What I needed was to be able to access the files from Mac OS X, because I know how to use that. So, I decided to try and install Mac OS on an external USB disk (80gb) and it worked! Yay! It took about an hour and required about 12Gb of the disk but now I can boot my MacBook in OS X. The only thing I had to do was to ''Skip" the DVD validation because by the time it had finished doing that the USB disk had disconnected (I don't know why that is) Once it booted and I went through the initial config it gave me a message saying it was unable to repair "MacBook Pro HD" and I should back it up and erase it. So, that's what I did (by copying the contents on to the external disk) and I know have a copy of the data that I thought I had lost and can now erase the internal HDD and re-install Mac OS X on to it. The reason i am writing this down is because I hunted high and low on the internet/forums last night for a simple guide to recovering my disk and found hardly anything (can't even find an explanation for the Control Key modifier in the Startup Manager!) so hopefully this will help someone that finds themselves in the same situation! JT.