I'm really keen to do an EFI install of x64 Vista. So far I've had no success. Until yesterday I'd not heard of anyone else having success either. Now I've exchanged emails with someone who may know someone who _has_ possibly succeeded! A few molecules of possibility drift through the aether. As you can see, I'm not being too committal at this point. I want to see proof first. And if any of you lot have done it, that's terrific, please tell us about it! A description of what I've tried so far follows. This is quite lengthy and probably very boring, and I don't expect you all to read it. Still, I'll throw it out there in case (small probability) it is of interest to someone. First off, the configuration: 2008 Mac Pro Firmware: MP31.006C.B05 (the latest) 2 x WD3200AAJS Western Digital Sata drives. Vista x64 SP1 DVD Disk 0 in bay 1 is the my GPT OS X disk. Disk 1 in bay 2 is to be the Vista disk. Note: disk numbers start from 0, disk bays from 1. Attempt 1. First I format disk 1 at the command line: diskutil eraseDisk MS-DOS Windows MBRFormat disk1 Then I reboot, hold down ALT, and select the EFI DVD boot image. The Windows installer loads, but I get this message when I select disk 1 as the target volume: "Windows is unable to find a system volume that meets its criteria for installation" I have no luck reformatting it, adding or deleting partitions, or doing anything else to convince Windows to install there. Attempt 2. I format disk 1 in Disk Utility. I select the disk itself (not any partition thereof), and make these choices: Volume Format: MS-DOS (FAT) Name: Windows Then I hit "Erase...", then "Erase" and I reboot and hold down ALT as before. Once more I select the EFI option and hit return. This time the screen switches to low resolution mode, goes black, a flashing cursor appears in the top left corner but the Windows Installer does not load. Silence. I reboot and choose the BIOS installation option and that does succeed, but I'm not totally happy with that. Give me my EFI dudes! Attempt 3. Windows has already been installed to disk 1, but I think I'll have another go at an EFI install. Maybe it will be easier to install over a previous install? So I boot and hold down the ALT key. I select once again the EFI DVD image and hit RETURN. The screen flickers, changes resolution and goes black. And then the Windows progress bar appears. Blast it! It's not booting off the DVD, even though I selected that. It is booting of the already installed version of Windows on disk 1. Attempt 4. Ok, so maybe the ALT thing is causing trouble. Perhaps if I reboot holding down C this time, it will force the DVD installer to load. I do this. The DVD can be heard spinning - good sign. But the screen is absolutely black. After a while nothing, not a whisper. Hmm.. what to do? It occurs to me that maybe the options are there, it's just that they're not visible. Maybe I should be seeing the infamous screen that looks like this: Code: 1. 2. Select CD-ROM Boot Type : On a hunch I click 2 and the DVD spins up again, and keeps spinning for a good while. Something's happening obviously, but I still can't see a thing on the screen. My suspicion is that the Windows installer has loaded, and is ready to install Windows, but the graphics stuff is messed up. Proceeding any further and doing a blind installation is not something a sane person would do. Or is it? I could go through the BIOS installation - a dry run if you like - and hope that the EFI installer works the same way. Then I would hit the exact same keys at the exact same sequence in the hope that it all works out. It's a bit mad, though, to do it that way. Anything could go wrong. I could end up installing over my OS X volume.