I did the upgrade last night. I got a message telling me that the update had failed and now it won't boot. I get the chime, the grey bar moves about half a centimetre and then in powers off. I can get into the recovery partition and run disk utility, it tells me this: Invalid node structure The volume Macintosh HD could not be verified completely. Error: this disk needs to be repaired. The repair fails: Error: Disk Utility can't repair this disk. I'm not going to waste time looking for a fix as it was a fresh install of Lion before the upgrade anyway, but I thought I should post about it anyway. I'm running an SSD, in case that's relevant. ---------- Turns out it's not so easy. I booted into the Lion USB key, hit install and now it's telling me that 'this disk is locked' and I can't click it to install the OS. I'll have to call Apple.