Best way to create Win 10 bootable external drive

[D_Newbie]

Hello all, after scouring the internet I haven't found much info that is up-to-date on this topic. I'm looking for the best way to boot Windows 10 from an external drive. Here's the scene:

-I have an iMac 2020 running Ventura, but only 500GB internal SSD.
-I have a 2TB USB 3.2 get 2 SSD.
-I want to boot Windows 10 from the external drive (rather than boot it from my tiny internal SSD...although size doesn't matter...and all that).

I've read that bootcamp works, but only for the internal drive. I also read about a workaround to that, but it's old info. I tried to use Etcher on my iMac to do this, but ran into issues. I've heard it's possible through Rufus (if there's access to a Windows machine...which I have).

Has anyone had success doing this? Most info I've found is out of date...THX!!!

 

[MacsBug]

I have actually done this in the past. Luckily i kept my notes on how I was able to do this, and I can test to see if it still works on the newer Macs with Windows 10 tomorrow and get back to you.

According to the notes that I wrote the external drive needed to be setup in Windows. So you may need to install a small bootcamp partition with Windows 10 to set this up. Then after things are setup, you can then delete the bootcamp partition.

 

[D_Newbie]

I have actually done this in the past. Luckily i kept my notes on how I was able to do this, and I can test to see if it still works on the newer Macs with Windows 10 tomorrow and get back to you.

According to the notes that I wrote the external drive needed to be setup in Windows. So you may need to install a small bootcamp partition with Windows 10 to set this up. Then after things are setup, you can then delete the bootcamp partition.

Any help would be really appreciated. I have found very few articles that are up to date on this topic. I've found lots of comments from people who couldn't get it to work! I only have a 500GB internal SSD, and I'd hate to take up half of that for Windows when it's not my primary OS. I'd love to hear whatever input you could offer.

 

[MacsBug]

I was able to successfully install Windows on a 2TB External SSD.

In order to do this, you will need the following items.

1. 16GB or Larger Flash drive formatted as FAT32 or ExFAT
2. USB Keyboard
3. USB Mouse
4. Windows 10 License Key

Here are the detailed instructions on how to set this up.


Plug in the SSD that you want into the Mac and use Disk Utility format it as MS-DOS(FAT) with Master Boot Record

Disconnect the SSD

Download Windows 10 ISO from https://www.microsoft.com/en-us/software-download/windows10ISO, and place it on your Desktop.

Open Boot Camp Assistant and under the Actions menu download the Windows Support Software.

Plug in the Flash Drive and copy the BootCamp & $WinPEDriver$ folders from the WindowsSupport folder , and the Windows 10 iso to the Flash Drive.

Unplug the Flash Drive

Use Boot Camp Assistant to create a Boot Camp partition and install Windows

Your Mac will restart into Windows.

After Windows is setup...

Connect the SSD to Windows to prepare it for Windows boot:

Run Command Prompt as Administrator, and then run the following commands:

diskpart​

list disk (Take note of the disk you want to use)​

select disk 1 (if your disk is Disk 1)​

clean​

convert gpt​

create partition EFI size=100​

format quick fs=fat32 label=EFI​

assign letter=S​

create partition primary​

format fs=ntfs quick label=Windows​

assign letter=E​

exit​

exit​

Download and install WinToUSB from https://www.easyuefi.com/wintousb

Plug in the Flash Drive

Run WinToUSB to install Windows on the SSD. You will need the ISO that is on the Flash Drive
Note: Make sure you install the proper version for your license

When this is complete, Exit and then Restart your Mac into macOS.

Use Boot Camp Assistant to restore your drive to a single partition.

Restart while holding down the Option Key

Select EFI Boot

*** You need to plug in a USB Keyboard and Mouse for the next step.

Finish Setting up Windows

Plug in the Flash Drive and run Setup.exe in the BootCamp folder.

When complete, unplug the USB Keyboard and Mouse

After this is done, whenever you want to boot Windows, just restart holding down the Option key and select EFI Boot

 

[D_Newbie]

MacsBug,

huge thanks for your time on this. I'll try it and let you know as soon as I'm able to screw things up...

 

[MacsBug]

Let me know how it goes.

I am including the instructions in a PDF so that you can download and print them out since you need to do a lot of the steps in Windows.

 

[D_Newbie]

MacsBug,

Can you weigh-in on something? (or anyone else who may know the answer to this question...)

According to this recent article on MacHow2 (click here for article) it states that bootstrap is able to download a copy of Windows 10 for an Intel Mac, which can then be used without an activation code. Is that true? Because that's all I have at this point (I don't have a copy with a code, just the ISO that bootcamp downloads). BTW, that article outlines the method I tried first but got hung up...

Also just FYI the pdf link you created didn't work for me but no worries. I just copied your instructions from the thread...