I've got a somewhat older macbook pro (mid 2014) and it starts lagging. And since I'm working professionally on it I'm thinking of buying a new macbook or Win laptop. But since I never had a clean install I first want to try a few things.

Clean up internals, new cooling paste and clean OS install. But since I'm also thinking of switching from Mac to Windows I also want a dual boot of Win10. So I can try working with Windows for a month. Since I will be switching between operating systems I want to have an additional volume for all my work files.

But I'm not sure how to partition the 1tb ssd.

  • What partitions would I need and what type
  • Would there be performance issues working on a volume type that one of both don't prefer?

I'm thinking of, first make 3 volumes, install Mac OS, then on create a boot camp with Boot Camp Assistant.

Any help would be welcome

  • ok, comment gone.
    – Tetsujin
    Jun 11, 2020 at 17:35

4 Answers 4


Steps to do a clean install of macOS and Windows

To do a clean install of the current versions of macOS and Windows, preform the following steps.

  1. Boot to a macOS installation media. For example, this could be a Mojave recover volume, internet recovery or a installation flash drive.
  2. Use the Disk Utility to erase the drive and create a single APFS volume.
  3. Install Mojave to this volume.
  4. Use the Boot Camp Assistant to install Windows 10. Include space for the MS-DOS (FAT) or ExFAT volume to be shared.

Steps to create a shared volume

This is to be done after installing macOS and Windows.

To create a MS-DOS (FAT) or ExFAT volume to be shared, preform the following steps.

  1. Under Windows 10, open Disk Management. Highlight the BOOTCAMP volume and select Shrink Volume…, as shown below.


  2. Select the desired size, as shown below. Next, select the Shrink button,


  3. Highlight the unallocated space and select New Simple Volume…, as shown below.


  4. When the image shown below appears, select the Next button.


  5. When a image similar to the image shown below appears, select the Next button.


  6. In desired select a different drive letter, then select the Next button.


  7. Select FAT32 and enter a volume label, as shown below. When finished select the Next button.


  8. When a image similar to the image shown below appears, select the Finish button.


  9. The result is shown below.


  10. If you wanted ExFAT format, then restart back to macOS. Use the Disk Utility to erase the volume. Enter a name and ExFAT format, as shown below. When finished, select the Erase button.

Note about the Golden Rule

There is a Golden Rule which can be loosely stated as:

Never change the partitioning on a Mac from Windows.

In this case, the Golden Rule does not apply for the following reasons.

  • There no Mac OS Extended volumes on the drive.
  • Windows is installed to UEFI boot.
  • Thanks for your extensive answer. I wanted to ask why you would include the shared volume space withing the windows bootcamp volume. But I get it now. Since you cannot reserve free space with the boot camp assistant. Without your answer I would have created 3 volumes with the Disk Utility in the Mac OS installer. Thanks
    – Tim
    Jun 11, 2020 at 19:34

Bootcamp allows you to boot into Windows on your Mac. Once installed, you will choose to boot to Windows or MacOS.

If you wish your Mac to dual boot Windows, you must use the Bootcamp installer. If you do not, you won't be able to boot into Windows or often get it installed. You can likely search google for many suggestions to install it outside of Bootcamp, but I think you will find most are not successful.

My recommendation is that you do not do any of the partitioning yourself, instead, the Bootcamp installer will do the partitioning for you. It requires a minimum of 64GB, but you should assign what you think you will need for your use of Windows. You could start by splitting the 1TB in half for each OS. The volume type etc are not important, the Bootcamp utility will do that for you. Your MacOS partitions will be APFS unless you choose to go with HFS+. Your new Mac will come with two partitions out of the box, one of them invisible (recovery).

Its hard to tell from your question if you are planning a Hackintosh or a Macbook. If a Macbook, there is no way to put in cooling paste, etc. And I am not clear on what 3 volumes will get you, but note that you do not create the Windows volume from the Disk Utility in Mac. The Windows volume is in many respects 'invisible' to MacOS.

If you decide not to dual boot with Windows, you can always remove that partition later.

For more on Bootcamp, see this Apple Support doc: https://support.apple.com/en-us/HT201468


HI dear I wanted to direct you using a boot-loader which allowed me to do what you exactly wanted but after thinking a while I thought this link would highlight the way better the way I did it with my own solution cause it had some glitches with over-heating my macBook. Below is the link you will find useful:


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    – fsb
    Jun 11, 2020 at 15:50

Follow this solution if you want to freely define the size of the shared volume, not rely on any Filesystem-Driver and access the shared partition from both operating systems natively.

  1. Install macOS
  2. Use the BootCamp Assistant to install Windows, this will create the Bootcamp partition. Give enough disk space for Windows but you don't have to include the disk space that you want to share.
  3. Use Disk Utility to create a new partition (not only a Volume) on the disk where macOS is installed. Now you decide how big the shared disk will be. Although you are creating an APFS-partitioned disk you will no longer be able to resize it later because we are going to change it to exFAT.
  4. In Disk Utility change the view-mode to View all devices, then you can reformat the disk partition to exFAT. Like described here . Since you're not going to erase a thumb drive, you might get failure messages because the disk is in use by some application. Eject the disk and if necessary force eject: repeat until erasing to exFAT succeeds.
  5. Now you have a shared disk that can be accessed from both operating systems.

If you want to have your home folder on the shared disk, follow this instruction. On the Windows side you will have to right click all of the Profile-Folders (Documents, Pictures, Movies,...) and select their new location on the shared disk.

If you are going to boot into Windows both natively as well as from the virtualization software Parallels, there are some more points you have to take care of (for other virtualization machines similar issues might arise):

  • In the Settings of your virtual machine unset share your profile with Windows and preferrably do not map the mac drives to windows. Instead share only custom folders and select the shared disk. The shared disk will be visible in Windows as Z: . If you share several drives or are mapping the mac drives the drive-letter might change to Y: , X: ,...
  • When booting into Windows natively, the drive will still appear with the letter D: . To keep the letter and all the paths consistent independently of the booting mode, open Disk Management, select the partition and give it the same letter that it gets when Windows is booted as virtual machine. You will get a warning that changing the letter might break some paths, confirm it.

Before coming up with this solution, I tried the solution proposed by David Andersson. But I found out, that there is one big problem: the shared volume you create out of the Bootcamp-Partition will be at maximum 50% of the original Bootcamp partition. This because Windows places some not-relocable system-files in the middle of the partition. I've even tried to resize the partition with a third-party tool (AOMEI Partition Assistant as well as Minitool Partition Wizard). Both did either fail during execution, or corrupted the partitions putting me back to the bottom of the stairs.

I also tried to keep the shared partition in APFS and install an APFS-Driver software to Windows. At first sight APFS for Windows seemed to be a good choice to a fair price. But after one month of troubles and a completely non existing customer service, I can only discourage this way. The issues I faced are that Excel was not able to open *.xls and *.csv files nor to save *.xlsx files. Visual Studio was not able to start debug sessions. The files could be opened with a text editor or copied to another location. If copied to a NTFS-Drive or when Windows was booted as virtual machine those problems disappeared, so the problem was clearly related to APFS for Windows, the files itself were not damaged.

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