Dual-Boot macOS on a drive with Windows 10 already installed (Shared Drive)

One of the things holding back a potential hackintosher from trying to hackintosh or install macOS on their PC is that they have only one hard drive and that hard drive already has Windows installed on it with no secondary backup or second drive to spare. There is actually a way to install macOS on a drive that already has Windows installed on it without having to delete Windows, but this will only work if the Windows disk is GPT formatted.

Step 1: Verify GPT Partition Type

  1. Install MiniTool Partition Wizard Free Edition
  2. Open MiniTool Partition Wizard
  3. Verify your Disk is GPT partitioned and has an EFI system partition. If the drive is formatted as MBR you are out of luck and can’t follow this guide. You’re only option would be to reinstall Windows in UEFI mode or install macOS first.

Verify Windows GPT and EFI Existence

Step 2: Resize Windows EFI for macOS

When a hard drive is formatted in Windows or macOS it creates a hidden partition called “EFI” macOS requires an EFI partition of 200MB in size to install macOS, but if you’re drive was formatted using Windows that EFI partition is only 100MB in size. So we need to increase the size of the partition to 200MB.

To increase the size of the EFI partition we need to take away space from the partition before or the partition after it. Everyone’s partition layout will look a little different.

As you can see in the image above to the left of my EFI partition I have the Windows Recovery partition and to my right I have the System Reserved partition / (Other) 16 MB. I’m not able to get enough free space from the Recovery partition or the small 16MB system reserved partition to reach 200MB. So my only option is to delete the System Reserved partition as it’s not as important to have as the Recovery partition. The reason I’m going to delete the System Reserved partition is because the EFI partition needs to be next to a partition like the C: partition which we can take space away from and I can’t do that the with System Reserved partition wedged between. I also can’t add space to the System Reserved partition and then add that space to the EFI so my only option is to delete. If your EFI partition is already next to a partition you can take away space from like a C: partition then you don’t need to delete.

  1. Right-click (Other) 16MB and select DeleteDelete System Reserved
  2. Right-click C: and select Move/Resize
  3. Change the GB labels to MB labels to make resizing easier
  4. Subtract enough space from Partition Size: to make Unallocated Space Before: 100.00 MB (For example I started out with Unallocated Space Before: 16.00 MB I subtracted 84.00 from Partition Size: I then set Unallocated Space After: 0.00 which automatically moves the space to Unallocated Space Before:)  Add Space to EFI Partition
  5. Click OK when done (You should now have 100 MB unallocated)
  6. Right-click the 100MB EFI partition and select Move/Resize
  7. Verify 200MB size change and click OK Change EFI Partition Size 200MB
  8. Right-click C: and select Split
  9. Set the partition size for macOS and click OK Step 9. Split C Drive
  10. Right-click new partition and select Format
  11. Set File System: Fat32 and click OK Format Hackintosh Partiton
  12. Click Apply at the top left of Partition Wizard
  13. Click Restart Now on prompt (MiniTools Partition Wizard will apply format changes to the drive on restart and then restart again brining you back into Windows. As it does this don’t touch anything.)

Step 1: Access macOS

To even make a flash drive with a Mac OS installer on it  you will first need either a. Access to a Mac or b. A virtual machine running macOS. If you do not have a Mac or one to borrow then create a virtual machine running macOS using one of the two links below depending on whether you are using Intel or AMD as your CPU/Processor.



Step 2: Make a macOS High Sierra Hackintosh

Before you begin installing Mac OS  there are two important things you need to know before you begin. When you first boot the macOS flash drive installer and open Disk Utility, you will select the Fat32 hackintosh partition you made in Step 1.11 and click Erase. You will then set Format: Mac OS Extended (Journeled) 

Format Fat32 Windows Partition Mac OS

The second important part comes when you boot Mac OS on your hackintosh for the first time and merge the EFI folders of your boot drive EFI folder with the flash drive EFI, which you’ll do once you reach this step. I would make a .zip backup of your boot drive EFI before the merge just in case you mess things up when you merge the flash drive’s EFI folder with the boot drive EFI folder.

Now that we have access to macOS we will now create a flash drive installer containing macOS install files and then install macOS. Based on what CPU/Processor you are using following the full guide below and then return to this one once you have macOS running. Just os you know you will need to completely wipe the drive you are using in order to format as GUID using Disk Utility. Also after macOS keep the flash drive the way it is as you will need it later.



Step 3: Dual-Boot Mac OS and Windows 10 using Clover

The last step is be able to boot boot Windows 10 and Mac OS using Clover EFI Bootloader to do that follow Step 5 & 6 of this guide: Hackintosh Dual Boot Windows 10 and macOS High Sierra (Same Drive)

Hackintosh Dual Boot Windows 10 and macOS High Sierra (Same Drive)

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7 Comments on "Dual-Boot macOS on a drive with Windows 10 already installed (Shared Drive)"

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WTF has happened to this site? It’s totally covered in ads now?


Is there a difference when installing macOS on a physically different hard drive than my already installed Windows10? Can I skip STEP 2: RESIZE WINDOWS EFI FOR MACOS this way? 🙂


i have full macos on it can i install it easier and will it be safe to have auto update from window 10


Can I partition an existing NTFS drive such that it has a Mac GUID partition that I can then install High Sierra on?