No Bootcamp on new iMacs?

Discussion in 'iMac' started by connor.e, Nov 6, 2012.

  1. connor.e macrumors member

    Jul 15, 2011
    There have been a few people who've mentioned this problem over the past few weeks, however, we simply haven't gotten to the bottom of it.

    Currently, Bootcamp does not work on HDD's over 2 TB. Why is this? If I'm to order a new iMac with a 3TB 7200 RPM HDD, should I expect Bootcamp to fail? This has had me a little worried. Does anyone know if this a problem that Apple can fix in a software update? I don't want to make the mistake of ordering a 1 TB drive to run bootcamp, when a 3TB would soon support it...

    Any input would be most welcome! Thanks for your time! :)
  2. 81Steven macrumors regular

    Dec 10, 2011
  3. forty2j macrumors 68030


    Jul 11, 2008
    Yes, you should expect it to fail. Apple's support note says "at this time" it won't work on large drives. Who knows if they'll ever fix it; the problem is rooted in the ancient technology that underpins the Wintel architecture. (There isn't enough address space in a standard BIOS to find the boot record in a >2TB drive, and Bootcamp does some BIOS emulation.)

    If you have that much stuff and want Windows to work, I would suggest either:
    - Get the 1TB drive and use an external for the rest
    - See if an emulator like Parallels is suitable for your use case.
  4. 81Steven macrumors regular

    Dec 10, 2011
    I hope they'll fix soon, but how to know if they inted fix? :confused: .
    They should change bios emulation in to efi and permit windows to partition gpt instead of mbr...

    1tb and external drive si viable
    But is it possibile to Bootcamp win7 or win8 from external?
  5. diagnostics247 macrumors member


    Jul 29, 2012
    Currently, as far as I know, Windows machines need a mobo with a UEFI BIOS to read HDDs over 3TB. I don't know how Apple handles it's BIOS as I don't even own an iMac yet (saving!)

    But here is a good article regarding the topic:

    TL;DR The Problem: Legacy Addressing

    "This situation could have been avoided if the entire computer industry had future-proofed after enduring the 137GB (28-bit) limit problems that cropped up around the turn of the millennium. In truth, most vendors did--with the notable exception of Microsoft. The company chose not to implement support for anything larger than 2.2TB drives in any of its 32-bit consumer operating systems--including Windows 7. Microsoft even omitted support from 64-bit XP. If you were looking for a reason to move to 64-bit Windows 7, here it is--courtesy of a not so subtle (or particularly gracious) invitation from the industry giant.

    Fortunately, you can find drivers and utilities that allow you to use a 3TB drive as auxiliary storage with any flavor of Windows, XP or later. I say "auxiliary" because you can boot Windows from a 3TB drive only if it's 64-bit Vista or 64-bit Windows 7--and then, only if you have a PC with an EFI/UEFI BIOS. EFI is Intel's Extensible Firmware Interface, and UEFI (United EFI) is the nonproprietary version based on the 1.10 EFI spec. EFI assumes the hardware and operating system interfacing chores from the BIOS after startup. The technology has been around since--you guessed it--the turn of the millennium, when the 137GB problems surfaced. Unfortunately, with no mainstream OS support from Microsoft (which is actually on the UEFI board of directors), most motherboard vendors saw no reason to implement UEFI before now."

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