How do I create El Capitan bootable usb from Windows 11?

Yeah, I actually brought a 2012 MacBook Pro back to life not long ago, and I was in the same boat — only had a Windows 11 PC on hand. Most of those old guides with TransMac or DMG2IMG either don’t work anymore or get stuck halfway through. Here’s what worked for me — two solid methods that still do the job if you want to create El Capitan bootable USB from Windows 11.

Method 1: Using UltraDMG (easiest way)

I tried a few things before landing on this one. UltraDMG still works great on Windows 11 for making macOS USB installers — including older ones like El Capitan. Here’s what I did:

(1) Download and install UltraDMG (it’s one of the few tools that can properly write .dmg to USB in macOS format).

(2) Plug in an 8GB or larger USB drive and back up any data on it first.

(3) Open UltraDMG → go to the Burn tab → load your El Capitan.dmg file.

(4) Choose your USB drive, click Burn, and let it run (takes about 20–25 minutes).

(5) Once done, plug that USB into your old Mac, hold Option (⌥) while booting, and pick the installer.

If you want a “click and done” option, this is the most reliable way to create El Capitan bootable USB from Windows 11.

Method 2: Command-line approach (no third-party app)

If you’d rather go old-school, you can do it using only built-in Windows tools. It’s slower but works fine.

(1) Open Command Prompt as Administrator.

(2) Type the following:

diskpart
list disk
select disk X    (replace X with your USB number)
clean
create partition primary
format fs=fat32 quick
active
assign
exit

(3) Convert the .dmg to .iso using dmg2img (available on GitHub):

dmg2img ElCapitan.dmg ElCapitan.iso

(4) Mount the ISO (just double-click it in Windows 11).

(5) Copy all files from the mounted ISO to your USB manually.

That USB won’t be bootable on Windows, but your Mac will recognize it when booting. Insert it, hold Option (⌥) at startup, and select the installer.

Extra Tip: macOS Recovery

If the USB still won’t boot, remember that Macs made after 2011 have Internet Recovery built into firmware. You can reinstall macOS directly — hold Command + Option + R at startup.

Apple’s official guide:

How to download and install macOS - Apple Support

It connects to Apple’s servers and downloads the compatible macOS version automatically — no USB needed if Wi-Fi works.

If you want something quick and reliable — use UltraDMG.

If you prefer the manual route — go with diskpart + dmg2img.

Both can easily bring that 2012 Mac back to life without borrowing another Mac.

Samuelplly wrote:

Method 2: Command-line approach (no third-party app)

If you’d rather go old-school, you can do it using only built-in Windows tools. It’s slower but works fine.

(1) Open Command Prompt as Administrator.

(2) Type the following:

diskpart

list disk

select disk X (replace X with your USB number)

clean

create partition primary

format fs=fat32 quick

active

assign

exit

(3) Convert the .dmg to .iso using dmg2img (available on GitHub):

dmg2img ElCapitan.dmg ElCapitan.iso

(4) Mount the ISO (just double-click it in Windows 11).

(5) Copy all files from the mounted ISO to your USB manually.

That USB won’t be bootable on Windows, but your Mac will recognize it when booting. Insert it, hold Option (⌥) at startup, and select the installer.

This won't be bootable on any Mac as well since the installer DMG doesn't contain any boot files or OS. It contains a .pkg file which is a macOS executable file which will extract the real full macOS El Capitan installer into the Applications folder as a standard app called "Install OS X El Capitan". Don't rely on AI without actually verifying the information is correct. Apple has never released a DMG installer that contained a bootable macOS raw image.

You can create a macOS VM inside Windows so you can use the built-in createinstallmedia command to make El Capitan bootable USB from a Windows PC.

Step 1: Install a macOS virtual machine (e.g. in VirtualBox) inside your Windows 11 system.

Step 2: Pass through the USB to the VM so the VM sees the USB drive.

Step 3: Inside the macOS VM, use the createinstallmedia command (the official macOS method) to make a bootable USB.

For creating El Capitan bootable usb, pls copy and paste this command:

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/USBVolumeName --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction

(Replace USBVolumeName with the actual mounted USB name.)

Step 4: Eject the USB from the VM/macOS VM and then use it to install El Capitan from bootable USB on your Mac.

Method to Create a Bootable El Capitan USB from Windows 11

1. Prepare a USB Drive

• Use a USB drive of at least 8 GB.
• Format it to FAT32 or exFAT (preferably FAT32 for compatibility).

2. Extract the .dmg File

Use 7-Zip (free and open-source) to extract the .dmg file:

• Install 7-Zip.
• Right-click the .dmg file, choose 7-Zip > Extract Here or Extract to "ElCapitan".
• The extraction will produce a .img or similar filesystem.

3. Convert the .dmg to .img (if needed)

Sometimes, the .dmg is a container for the installer files.

Use dmg2img (free tool) to convert .dmg to .img:

• Download dmg2img.
• Run the command:

dmg2img path_to_your_dmg.dmg output_image.img

4. Write the Image to USB

Use balanaEtcher (free and cross-platform, works on Windows):

• Select the .img or extracted files.
• Choose your USB drive.
• Flash the image.

5. Make the USB Bootable for Mac

• This is the tricky part: macOS installers are designed to be run on Mac hardware.
• The created bootable USB may not be directly bootable on a PC, but if you have access to a Mac, the best way is to prepare the USB there:
• Use createinstallmedia command on a Mac:

sudo /Applications/Install\ OS\ X\ El\ Capitan.app/Contents/Resources/createinstallmedia --volume /Volumes/YourUSB --applicationpath /Applications/Install\ OS\ X\ El\ Capitan.app --nointeraction

If macOS is not currently installed or bootable on this 2012 laptop, then boot this laptop into Internet Recovery Mod using Command + Option + R to attempt to access the online macOS Catalina installer. Once you have macOS installed, then you can use the official Apple instructions to create a bootable macOS USB installer from the link provided by @Grant. Yes, it is a bit of work & a round about method, but it is ultimately the easiest.

You can try booting into the Lion or Mountain Lion depending on the model & when it was manufactured by using Command + Option + Shift + R, but many of those older online macOS installers have issues these days since Apple is not properly maintaining them. If this works, then you can copy the El Capitan installer DMG file to this Mac & install/upgrade to El Capitan.

Your best option though is hoping you can access the online Catalina installer.