Windows 10 for MacBook using BootCamp

You want to install Windows on your Mac to install unsupported software for MacOS. However, the hard drive is only 128GB. So, here is the instruction to install Windows on an external drive using BootCamp on your Mac.

Recently, I have received many emails from you saying that you bought a 128Gb MacBook due to its cheap price, but many of you still want to run Windows 10 OS on your Mac. It’s a legitimate requirement, so in this guide, I will show you detailed steps, easy to understand so that everyone can do this on their own.


  • Save up your Mactonish hard drive
  • Run smoothly over virtual machines like Vmware Fusion, Parallel


  • You need to connect the external drive when using Windows


  • A Windows Computer. If you cannot get it, you can install Windows using Parallel Desktop
  • An SSD drive or an USB (at least 32GB) to store Windows OS
  • Windows 10 ISO file
  • The latest free build from its official website does not allow creating a Windows 10 installation disc. 
  • Store Windows 10 ISO file and on the Windows computer

Once you meet all requirements, let’s start installing Windows 10 into an external drive to run it on your Mac. All the steps I did on my Mac running macOS 10.15 Catalina, but you can still apply these steps for other MacOS versions.

How to Install Windows 10 in an External Drive using BootCamp

Step 1: Download Driver Bootcamp

Open Bootcamp Assistant (Launchpad > Others>Bootcamp Assistant)

Select Action>Download Windows Support Software

In Save as box: type in WindowsSupport  and put it in Desktop of your Mac

Wait for about 15-20 minutes so that Bootcamp download and install driver. When prompted, enter the password of your Mac to save the file.

Step 2: Format Your External Drive

  • Connect your external hard drive into your Mac and open Disk Utility
  • Click on Scheme, and then select the following info:

Name: Boot Camp

Format: Mac OS Extended (Journaled)

Scheme: GUID Partition Map

  • Click on Erase after formatting your drive

Step 3: Create an External Bootable Windows 10 Flash Drive 

  • Re-partition the external drive

Connect your external drive into a Windows computer. If you are asked to format it in the popup, click on Cancel.

(If you are using Vmware Fusion 11, follow these steps below:

  • After plugging the drive, you will see a popup, asking you whether you want to connect it in MacOS or Windows environment.
  • Go to Disk Management by pressing Windows key > This PC and right click to choose Manage
  • In Disk Management screen,  right click on EFI partition (the second partition) and choose Delete Volume
  • Right click on recently Deleted Volume and select New Simple Volume
  • Follow the onscreen instruction until it finishes.
  • Once done, your external drive will have two partitions.
  • Now, install WintoUSB. When done, run  Hasleo WinToUSB file and then follow the image below. Browse to Windows 10 ISO file and select Windows 10 Pro 
  • Next, select GPT for UEFI. If you are using an SSD, there will not appear this window.
  • In Please select EFI system.. section, choose the small EFI 200MB that was previously created by Disk Utility, while in Please Select the boot partition, you select  BOOT CAMP partition. The installation mode is Legacy
  • Click on Yes and wait for the process to be done. It can take about 30-40 minutes.

Also read: How To Install Windows 10 On MacOS Using BootCamp

Step 4: Back to Mac Computer

  • Copy the WindowsSupport folder into your external drive. If you are not allowed to copy, you can install Paragon NTFS software to bypass it.
  • Once done, there will be folders like the image below
  • Restart your Mac, press and hold Option key while booting it up and select EFI Boot 
  • After booting into Windows, go to WindowsSupport  folder to install driver for Windows 10. 

That’s how to install Windows 10 on external drive using Boot Camp on Mac. If you have any question during the installation, let’s know in the comment below.


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