• Scenario *

The mid 2011 Mac all-in-one (21" and 27") is no longer supported by Apple. The latest OS that can be installed on a mid 2011 Mac is MacOS High Sierra v10.13.6. Much new software is not supported on that OS, essentially rendering the machine obsolete.

Support for BootCamp on this hardware is limited to Windows 7. Most (at least all of those I've been able to find) articles related to BootCamp and Windows 10 on forums state that Windows 10 can't be installed on these machines without loss of use of some hardware capabilities, particularly in terms of graphics and user input devices, if it can be installed at all.

I have achieved an installation of Windows 10 (Sep 2019) on a BootCamp partition with no loss of graphic resolution, access to BlueTooth, user input devices (except the Magic Mouse) or USB devices. Note that the Magic Mouse is not fully functional, lacking the touch sense functions, but left and right click still work. Any other scroll wheel mouse will work just fine.

This is a guide on the process I used to achieve the installation.

• Hardware *

The hardware I use is a mid 2011 27" all in one with a 3.4GHz quad core i7 processor, 16GB of 1333MHz DDR3 RAM, an AMD Radeon HD 6970M 2GB video controller and a 2TB HDD. In my view, this is much too high a specced machine to simply discard and makes a very respectable Windows PC. It will never be used as a Mac again. I have a new 2019 Mac to replace it.

• Prerequisites *

The SuperDrive optical drive must be fully functional. In my case, the drive had died a quiet death a few years ago, so I had to replace it. There is no getting away from using Apple's Boot Camp Assistant and this requires a fully functioning SuperDrive because you can't use a USB external drive or bootable USB image of Windows 7. There is a really good video on replacing the SuperDrive here: https://www.youtube.com/watch?v=3JqsCK-g8pg

Note that the video does not sufficiently caution on the fragility of the LVDS display port socket on the video card and the ribbon cable. Both can easily be damaged in re-assembly, thus rendering this exercise pointless.

You can get a replacement drive on eBay for about $70.

You must have a Windows 7 installer DVD. I used Windows 7 Pro with SP1. You must also have a Windows 10 installer DVD for the same edition (Pro).

I also used VMWare Fusion as an aid, but this may not have been necessary. In any case, the latest version of Fusion that will work in High Sierra is 11.1.0, which may not be obtainable from VMWare. I had it because I was using it on the machine anyway for other VMs.

• Procedure *

** Re-Initialise the Mac **

This procedure erases anything that is presently on the Mac, disconnects it from your Apple ID and reconfigures the HDD. If there is anything you want to save, back it up.

Follow the procedure here to re-initialise the Mac: https://support.apple.com/en-au/HT201065

** Disable SIP **

Once initialised, log in and reboot the Mac to the Recovery utilities: once the screen goes blank at shutdown, hold the Command and R keys together until the Apple logo appears on the screen. When the Recovery Utilities panel appears on the screen, choose the Utilities > Terminal option on the menu bar at the top of the screen.

In the terminal window, type the following command to remove the system integrity protection (for Mac OS):

csrutil enable --without fs && reboot

This may seem a matter of concern, but turning off protections that inhibit certain activities in Mac OS, which you are never going to use once Windows is properly installed, is irrelevant. If you don't turn SIP off, you will encounter issues later. If it makes you nervous though, the SIP can be restored in the Recovery Utilities terminal with this command at the end of the installation (although I didn't do this because I didn't want to take the risk that it might impact on the Windows installation later):

csrutil clear && reboot

** Install Windows 7 **

Insert a FAT32 formatted USB drive into a USB port on the back of the Mac. This is for the Boot Camp Assistant to save the Boot Camp drivers and access later. If this is not inserted before starting the Boot Camp Assistant, the procedure will fail.

Insert the Windows 7 installer DVD in the SuperDrive. If this is not inserted before starting the Boot Camp Assistant, the procedure will fail.

Start the Boot Camp Assistant from Launchpad > Other > Boot Camp Assistant. If the machine already has a Boot Camp partition (which it should not if you have correctly re-initialised the machine), remove it. You will then need to restart Boot Camp Assistant.

In Boot Camp Assistant, make sure both checkboxes are checked. Checking only one or the other will cause the procedure to fail.

Once the Boot Camp Assistant starts, it will download the Boot Camp drivers and save them to the USB drive, then move on to partitioning. Choose the size of the Boot Camp partition. If you are serious about using this machine as a Windows 10 only PC, you only need 200 to 300 GB left for OS X.

If you get the message 'Windows 10 is not supported' although you know the DVD is a Windows 7 installer, you have probably tried to skip download of the drivers or download was interrupted in some way or you inserted the installer DVD after the Assistant had started. There is a glitch in the Boot Camp Assistant whereby if any of the previous conditions have not been met precisely, the message will appear and installation will not proceed.

Once partitioned, Boot Camp Assistant will start installation of Windows 7.

In the partition list in the Windows 7 installer, you will probably see 4 partitions. The 4th partition is probably the largest, but you will likely see that partition marked with 'Windows cannot use this partition'. Be careful not to choose the OS X partition. Highlight the Boot Camp partition onto which you want to install Windows 7 and click the 'Format' hyperlink. The partition will be formatted in NTFS, the warning will go away and you will then be able to choose the partition for the installation.

After Windows 7 starts, allow BootCamp to install the Windows 7 drivers for the Apple hardware. Several reboots will be required before the whole thing is finished.

*** Create a Windows 7 Fusion VM from BootCamp (probably not necessary) ***

Reboot the Windows machine into Mac OS. Use the Boot Camp icon in the system tray and choose 'Restart in OS X...'

Start VMWare Fusion and choose to create a VM from a Boot Camp partition. Start it up. Fusion will install its Windows 7 drivers.

If the VM won't start, you probably skipped the bit about disabling SIP and will have to delete the VM, disable SIP and re-create the VM.

Shut down the VM.

Boot to the Windows partition using System Preferences > Startup Disk and choose the Boot Camp partition.

** Upgrade to Windows 10 **

Eject the USB disk and the Windows 7 installer DVD: choose each in turn in Windows Explorer, right click and Eject.

Insert the Windows 10 installer DVD and run Setup. Windows 10 will happily upgrade Windows 7 in place.

Once Windows 10 installation is complete, you will be tempted to choose a screen resolution more to your liking. Don't, because there isn't one until after the finish up.

*** Start Fusion VM with Windows 10 Installed (probably not necessary) ***

As with the post Windows 7 install, boot back in to OS X and run the Fusion Boot Camp VM.

Shut down the Fusion VM and boot back in to the Boot Camp partition.

• Finishing Up *

Leave the PC powered up, logged in and connected to the internet and wait for Windows 10 Update to find missing drivers. You will find that audio, network and video drivers will download and install without your intervention. Particularly gratifying was the installation of the AMD Catalyst Control Center and drivers giving full resolution at 2560 x 1440.

After a couple of reboots, the Windows 10 installation will be running at full screen and you will have a rather well specced PC that will play DVDs (with appropriate software, like K-Lite Codec Pack) and run all Windows 10 supported software.

Notes:

o I do not provide support for this procedure.

o I cannot provide any of the software mentioned in this procedure.

o Windows 7, Windows 10, VMWare and Apple names and trademarks are the property of their respective owners.