I wiill check it and try to confirm it. Testing on msi gx serie based laptop, which have only ahci enable/disable option in bios. As i am aware IRRT is not suported by hardware. I tried it. 1st part of install pass well, but it fails with a hal error at the boot of 2nd. Not sure if its related to the 'unknown error'... This would be a nice testing machine... 1) Can you check what has been written in boot.ini in the internal disk? You may use some live distro, XP Recovery Console, or even grub4dos: find /boot.iniif the output is like (hd0,1) then type: cat (hd0,1)/boot.ini 2) Did you start from USB for the second part, the GUI mode? 3) Did you use PLoP by any chance? 4) In grub4dos CLI (press "c" when you see boot menu entries) type the following: root ( and press [TAB] right after (, what's the result? geometry (hd99) and [ENTER] , what's the result? find /usbdrive.tag[ENTER] , what's the result? Iread your post too late:( Already installed it using the stable version. I will try to test it again this week. 1Can you check what has been written in boot.ini in the internal disk? I checked while and i am sure it was some random seed. 2Did you start from USB for the second part, the GUI mode? Yes 3Did you use PLoP by any chance? Yes.Both ways.With plop is very fast, but the same error persisted so i supose it isnt related. In grub4dos CLI (press "c" when you see boot menu entries) type the following:root ( and press [TAB] right after (, what's the result? I will check it with the next test. I am sorry cant be of much help right now, but will post as soon as possible with more detalled information.