Having tried this before and rendered the mac partition unbootable, I decided to try again.

With help, I managed to retrieve my data, wipe the HDD and reinstall Mac OS Sierra via internet recovery. Now I am trying to reinstall Windows 10 and then Ubuntu 16.04 but am stuck at the first hurdle.

I tried to use Boot Camp assistant to create a new partition for Windows but was informed that Windows 10 is unsupported on this Mac (Windows 10 was previously running on this machine but I had updated from Windows 8.1). No problem, thought I, I'll just dig out the Windows 8.1 DVD... Same message as before: "Windows 10 cannot be installed on this Mac" eh? Not wishing to give up, I made a FAT partition using Disk Utility.

I then made another partition for the future Linux install. Feeling optimistic, I booted from the Windows 10 DVD in legacy mode and got to the point where you choose which partition to install Windows on. I keep getting the message "Windows cannot be installed on this partition" even when I format or delete the partition to leave free space.

Last time I "solved" this problem by booting in EFI mode and installing that way. This broke the partition map and left Mac OS unbootable.

What is the best way to install Windows on the partition without destroying the ability to boot Mac OS too? Really, I would like to then install Ubuntu on the other partition but one thing at a time...

I have read other posts on this topic but the solutions suggested do not seem to work in this situation.

Output from Diskutil list:

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Mac OS                  1.5 TB     disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data BOOTCAMP                514.0 GB   disk0s4

The iMac has 8GB of RAM and I want the OSs to have roughly the space shown above. I have not started to install Linux yet and the Windows has failed to install so far.

OK so I have managed to install Windows 7 via bootcamp and then update to Windows 10, good so far, both OSs booting. Then I re-sized the Bootcamp partition from Windows to make space for Linux but guess what? The partition editor won't let me create a new partition in the unallocated space and Ubuntu won't install into it. I have already got 4 primary partitions and no more is possible. Still, I've got two OSs working again...I have updated the diskutil list and it doesn't show the resized windows partition. Is there any way of installing Linux in the free space without wrecking everything?

OK, so I went ahead and made 3 new partitions using Disk Utility and installed Ubuntu 16.04 onto them following instructions from Installing Ubuntu on Mac with macOS and Windows already installed Result: Mac and Ubuntu still boot fine but Windows now won't boot and gives a message " Missing Operating System" when I try to boot from it.

This is the new diskutil list output:

    /dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS Mac OS                  1.3 TB     disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:                        EFI                         6.5 GB     disk0s4
   5:           Linux Filesystem                         198.7 GB   disk0s5
   6:                 Linux Swap                         15.2 GB    disk0s6
   7:       Microsoft Basic Data BOOTCAMP                514.0 GB   disk0s7

Anyone got any ideas for how I can rescue the Windows install?

  • 2011 is a very old system, and Windows 10 has certain requirements and deprecated many old hardware components. That could be a problem. As a tangential "solution" have you considered running a Windows VM through something like VirtualBox, or Windows emulator, like Wine?
    – MikeP
    Commented Mar 29, 2018 at 20:07
  • Until I tried to triple boot and had to wipe the drive, Windows 10 was running fine on this system. The weird thing is that even when I tried to install 8.1, Bootcamp still wouldn't install because it "thought" I was trying to install 10. Commented Mar 30, 2018 at 9:39
  • What do you mean by 2011 iMac 11.3? I can interpret this to mean one of the following: iMac11,3 (27-inch, Mid 2010), iMac12,1 (21.5-inch, Mid 2011), iMac12,1 (27-inch, Mid 2011) or iMac12,1 (21.5-inch, Late 2011). Commented Mar 30, 2018 at 12:32
  • its the mid 2010 one. Commented Mar 30, 2018 at 20:39
  • Add the output from diskutil list to your question. If is difficult to post an answer without knowing something about how your computer is partitioned. I also need to know how much RAM is installed. How much drive space do you what Windows and Ubuntu to occupy? Commented Mar 31, 2018 at 4:12

2 Answers 2


Whatever happens, don't worry, because

You only lose what you haven't backed up™

So, if you don't have a backup of your system, make sure you create one:

  1. Download and install "CloneZilla", a FOSS disk cloning utility, on a USB drive, in UEFI mode. Google is your friend, but this is a guide for you
  2. Now attach a blank HDD the size of your hard drive and reboot your Mac in Clonezilla
  3. Clone your internal hard drive over to the backup disk (make sure you don't do the other way around). The interface is pretty intuitive, but the procedure could take a while, regardless of how much data you have on your disk.

Now, make an ExFat partition on your disk using Disk Utility, launch the Windows installer, format it and install Windows.

Apparently in your case this seems not to be working and - in EFI mode - Windows messes up your EFI system.

I have a couple of suggestions.

The first: install Windows on a secondary HDD. This makes everything much easier, and you don't have to deal with countless other issues such as messed up partition tables and wrongly erased volumes. IIRC a secondary Hard drive can be installed in your system and - considering how cheap they are - it's really worth it.

The second, and most complicated (and maybe dangerous) is to run an Ubuntu (or any other distro) live session, open GParted, unmark your EFI partition as such (making it not appear as an ESP, but rather as a generic partition) and create two ExFat partitions. The first of them has to be very tiny (~200 MiB) marked as ESP, the other one - instead - should be as big as you want your Windows C: to be. After this is done, install Windows in EFI mode to the big ExFat partition (after having formatted it), then re-run GParted and re-mark the original ESP as such again. Now you can install rEFInd from macOS and boot your system in Windows by selecting the secondary ESP you created upon boot. If so you want, you can tweak rEFInd to boot an OS automatically by default, have a custom theme and do many other fancy things.

If you have no idea on how to do all of this, I'd recommend against doing it. Also remember that it's old hardware we are dealing with, so compatibility might not be the best, if existent at all.

  • EFI installs of Windows did not occur until at least the 2012 model year. I am not saying your answer is wrong for all Macs, but it is wrong for a 2011 iMac. Commented Mar 30, 2018 at 10:52
  • @DavidAnderson you can still try to install it. You don't necessarily need to use BootCamp.
    – Manchineel
    Commented Mar 30, 2018 at 12:10
  • What part of Boot Camp are your referring to? Do you mean the Boot Camp Assistant or the Boot Camp Support Software? Commented Mar 30, 2018 at 12:20
  • @DavidAnderson oh sorry, I nearly forgot BootCamp is not one single thing. I meant, just the Assistant, of course you can't do without the Support Software
    – Manchineel
    Commented Mar 31, 2018 at 8:11

Below is my list of best practices.

  • Ubuntu normally runs with a separate swap partition. This means you need at create at least two partitions when installing Ubuntu.

  • After installing Ubuntu, you should not rename or copy any of the installed files. Often, this is done in order to make Ubuntu bootable on Mac computers. Later, these modifications may cause problems when Ubuntu is updated.

  • You should probably avoid using APFS. Many posts have documented problems where Windows can not read APFS formatted volumes. Also, the Windows Boot Camp software can not detect APFS volumes. This makes booting from Widows to macOS more difficult. Also, users have complained about macOS upgrades preventing Windows from booting on older Macs.

  • All bootable operating systems should be accessible from the Startup Manager. In other words, each operating system should be installed so it can be booted without first booting from another operating system.

  • There should be at least one FAT32 or ExFat formatted partition accessible from all operating systems.

  • rEFInd should be used to silently boot Ubuntu (by first booting GRUB). The Startup Manager should be used to boot rEFInd. In your case, rEFInd can be installed either in the EFI partition of a small jHFS+ partition.

Below is an example of the partitioning currently being used on a 2007 iMac.

Steelhead:~ davidanderson$ diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:       Microsoft Basic Data Shark                   202.0 GB   disk0s2
   3:       Microsoft Basic Data Shark2                  202.0 GB   disk0s3
   4:       Microsoft Basic Data SHARK3                  50.0 GB    disk0s4
   5:                  Apple_HFS Steelhead               245.1 GB   disk0s5
   6:                 Apple_Boot Recovery HD             650.0 MB   disk0s6
   7:                  Apple_HFS Ubuntu                  199.2 MB   disk0s7
   8:                 Linux Swap                         4.3 GB     disk0s8
   9:           Linux Filesystem                         93.9 GB    disk0s9
  10:                  Apple_HFS Steelhead2              198.9 GB   disk0s10
  11:                 Apple_Boot Recovery HD             650.0 MB   disk0s11
  12:                        EFI REFIND                  134.2 MB   disk0s12
Steelhead:~ davidanderson$ sudo gpt -r show /dev/disk0
gpt show: /dev/disk0: Suspicious MBR at sector 0
       start        size  index  contents
           0           1         MBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34           6         
          40      409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
      409640        2008         
      411648   394530816      2  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
   394942464   394530816      3  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
   789473280    97654784      4  GPT part - EBD0A0A2-B9E5-4433-87C0-68B6B72699C7
   887128064      262144         
   887390208   478769528      5  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1366159736     1269536      6  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  1367429272     3893096         
  1371322368      389120      7  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1371711488     8390656      8  GPT part - 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F
  1380102144   183320576      9  GPT part - 0FC63DAF-8483-4772-8E79-3D69D8477DE4
  1563422720        1760         
  1563424480   388568960     10  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
  1951993440     1269544     11  GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
  1953262984      262144     12  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
  1953525128           7         
  1953525135          32         Sec GPT table
  1953525167           1         Sec GPT header

Some notes:

  • An EFI partition is the 1st partition. This is where the Ubuntu installer put the Ubuntu GRUB boot code.
  • Windows 10 is installed on the 2nd partition.
  • Partitions 2, 3, and 4 are visible to all operating systems.
  • Partitions 4 is FAT32 formatted. This is read/writeable to all operating systems.
  • Partition 5 has Yosemite OS X 10.10 installed.
  • Partition 6 is the recovery partition for Yosemite.
  • Partition 7 is a small Macintosh Extended (Journaled) formatted partition where rEFInd is installed. When this partition boots, rEFInd then silently boots the Ubuntu GRUB code stored the the EFI partition. The "Ubuntu" label given to this volume will also appear as an icon label in the Startup Manager.
  • Partition 8 is the Ubuntu swap partition. The size is slightly larger than the 4 GB of RAM installed in the Mac.
  • Partition 9 is Ubuntu.
  • Partition 10 contains El Capitan OS X 10.11 which is the last version that will run on this Mac.
  • Partition 11 contains the El Capitan recovery partition.
  • Partition 12 is a second EFI partition. This contains a second copy of rEFInd. This partition was used for testing and could be deleted. None of the operating systems depend on this partition to boot.

In your case, you would need partitions 1, 2, and 4 through 9.

There are various ways to create the partitions. The choice depends on whether you are doing a fresh install of macOS or restoring from some other source. For Windows, the 2nd partition should be FAT32 formatted. I would suggest using a pure EFI partition scheme to first get macOS back on your Mac. Continue with pure EFI partition during the Ubuntu install. The last operating system to install would be Windows, but you will have to switch to a hybrid MBR/EFI partitioning scheme before starting the Windows installer. You will need to instruct the Windows installer to reformat the 2nd partition from FAT32 to NTFS.

I can give more detailed instructions, if you are interested.

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