Windows 8 Pre-install BSOD: IRQL not less or equal

Discussion in 'Windows, Linux & Others on the Mac' started by BrutalSpoon, May 1, 2013.

  1. BrutalSpoon macrumors newbie


    Dec 2, 2007
    London, UK
    Hi everyone!

    So, I figured I'd give Windows 8 a go on my MBP, which has a SSD and a data doubler with my old hard drive in it instead of the optical drive. I managed to get BootCamp 5 to create a bootable USB drive with a Windows 8 Pro x64 ISO with the BootCamp drivers - all fine there.

    I figured EFI booting would be the way to go, so I repartitioned my hard drive using Disk Utility - apparently no hassles there.

    However, I'm running into an error when I try to boot from the USB drive. When I hold down option on boot, I see the drive labelled as "EFI Boot". I select it, and the screen goes black with blue Windows logo (so far so good!). After 10 seconds or so a white progress indicator shows up, but after spinning once or twice it freezes.

    Suddenly, a wild BSOD appears! The standard text stays there for a few seconds; it only flashes the error for a split second before rebooting. It turned out to be "IRQL not less or equal".

    Obviously my google fu isn't quite up to scratch at the moment; after looking around I still don't have any answers. I thought it might have been a bad stick of RAM, but I've tried each stick individually (as well as some other RAM which I'm reasonably confident is fine) with no luck.

    I also thought that the transfer to the USB drive might not have worked properly, but I've used a couple of different drives. I've also checksummed the ISO, so I know the ISO isn't corrupted at all.

    So I turn to you, Mac Rumours denizens. Can you help me?


    TL;DR: Windows 8 installer gives a BSOD Error "IRQL not less or equal"; probably not bad RAM or installation media. Any ideas?
  2. Renzatic Suspended


    Aug 3, 2011
    Gramps, what the hell am I paying you for?
    An IRQL not less or equal usually means you've got a catastrophic driver issue or other hardware conflict (or bad ram, but you've already checked that). So something in your setup isn't gelling with Windows 8, and it's causing the install process to freak out and blue screen on you.

    My Google Fu is pretty decent, so I looked up this handy guide for you. Seems that installing Win8 EFI native on a Macbook is a fairly indepth process, so it's likely you've either missed something important, or didn't set something up quite right. Glance through it and see what it says.
  3. monkeybagel macrumors 65816

    Jul 24, 2011
    United States

    I have not been able to smoothly install Windows 8 (even though I don't like it) onto a 2012 15" MacBook Pro in EFI. It ends up hanging along the way. The only machine that I have been able to install Windows 8 in pure EFI mode is a 2012 Mac Pro. No magic, trickery, or anything. It just installs. And boots fast.
  4. BrutalSpoon thread starter macrumors newbie


    Dec 2, 2007
    London, UK
    Yeah, still no luck for me either.

    Renzatic, thank you for taking the time to look into it for me! Unfortunately, I think I'm getting the BSOD even earlier than the one referred to in that article; I don't get to any sort of setup screen or any repair/commandline windows.

    Is there any particular advantage to Windows 8 in EFI mode other than boot speed? I've seen plenty of things about sound/graphics not working for it, too. For that matter, are there any particular DISADVANTAGES to running Windows 8 via BIOS emulation?

    I might give W8 w/ BIOS emulation a go, otherwise it looks like I'm going back to Windows 7 again. Probably for the best anyway, but I thought I should give Windows 8 a proper go before I dismiss it altogether.

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