If your Mac refuses to start, gets stuck on the Apple logo, or needs a clean reinstall, a macOS bootable USB can save you hours of frustration. Normally, Apple expects you to create installers from another Mac — but what if you only have a Windows PC? The good news is, you can still create a fully working macOS installer using Windows, and it’s easier than most people think.
In this guide, I’ll walk you step-by-step through the entire process of creating a macOS bootable USB from a DMG file on a Windows computer. This method works for macOS Sonoma, Ventura, Monterey, Big Sur, Catalina, and older versions. Even if you’ve never done this before, just follow along carefully and you’ll have a ready-to-use macOS installer by the end.
Requirements
Before we start creating the macOS bootable USB, make sure you have everything ready. Preparing these in advance will make the process smooth and prevent errors halfway through.
You’ll need:
- A USB flash drive with at least 16GB storage
- A Windows PC (Windows 11, 10, 8, or 7)
- A macOS DMG installer file
- TransMac software
- A backup of your USB data
⚠️ Important: The USB drive will be completely erased during this process. If there are any important files on it, copy them somewhere safe before continuing.
Once these requirements are ready, we can move on to preparing the USB drive for macOS.
Step 1 — Prepare the USB Drive (Convert to GPT)
To make the USB compatible with Mac computers, we first need to convert it to the GPT partition scheme. This ensures the Mac can recognize and boot from the drive properly.
- Insert the USB drive into your Windows PC
- Open Command Prompt as Administrator
- Type the following command and press Enter:
diskpart
- Now type:
list disk
This shows all drives connected to your computer. Identify your USB drive by its size.
- Select the USB disk (replace X with your disk number):
select disk X
- Clean the USB drive:
clean
- Convert it to GPT:
convert gpt
- Create a primary partition:
create partition primary
Once these commands finish, your USB drive is properly prepared and ready for the macOS installer.
In the next step, we’ll download the macOS DMG file.
Step 2 — Download the macOS DMG File
Now we need the macOS installer image in DMG format. This file contains the full macOS setup that will be written to the USB drive.
Apple officially provides macOS downloads, but usually only older versions are available there. If you want newer versions like Sonoma or Ventura, Internet Archive is a reliable source where you can find installers for almost every macOS release.
👉 Important compatibility rule:
Your Mac cannot boot a macOS version older than the one it originally shipped with.
For example:
- A Mac that shipped with Monterey cannot boot Big Sur
- It can boot Monterey or newer versions like Ventura or Sonoma
So always choose a version that matches or exceeds your Mac’s original OS.
After downloading the DMG file, keep it somewhere easy to find, like your Desktop. In the next step, we’ll install the tool that writes this image to the USB.
Step 3 — Install TransMac
To write the DMG file onto the USB drive, we’ll use a tool called TransMac. Windows cannot natively create macOS bootable drives, so this software handles the Mac file system and restores the installer correctly.
TransMac is paid software, but it offers a 15-day free trial, which is more than enough for creating the installer.
Download and install it normally. After installation:
- Right-click TransMac
- Choose Run as Administrator
Running as administrator is important, otherwise the USB restore process may fail.
Once TransMac opens successfully, we’re ready to create the bootable installer in the next step.
Step 4 — Restore the DMG File to the USB
Now we’ll write the macOS installer onto the USB drive using TransMac. This is the step that actually creates the bootable installer.
Inside TransMac:
- Locate your USB drive in the left panel
- Right-click the USB drive
- Choose Restore with Disk Image
- Click Yes to confirm formatting
- Browse and select your macOS DMG file
- Click OK
TransMac will now start writing the installer to the USB.
⏳ This process can take 15–30 minutes depending on USB speed. The DMG file is large, so don’t interrupt the process. Let it finish completely.
Once TransMac shows that the restore is complete:
- Close the program
- Safely eject the USB drive from Windows
You now have a working macOS bootable USB.
Next, we’ll use it to boot a Mac and start installation.
Step 5 — Boot Your Mac from the USB Installer
Now that the bootable USB is ready, plug it into the Mac where you want to install macOS.
The way you access the boot menu depends on your Mac type:
For Apple Silicon Macs (M1, M2, M3)
- Shut down the Mac completely
- Press and hold the Power button
- Keep holding until you see Loading startup options
- Release the button
For Intel Macs
- Shut down the Mac
- Turn it on and immediately press and hold the Option (⌥) key
- Hold it until the boot menu appears
When the boot screen opens:
- Select the macOS installer USB drive
- Click Continue or press Enter
The macOS recovery environment will load, and the installation process will begin.
Installation can take 30–60 minutes, depending on your Mac and USB speed. Keep the USB connected until everything finishes.
In the next step, we’ll complete the macOS installation.
Step 6 — Install macOS from the USB
After booting from the USB installer, you’ll enter the macOS recovery environment. From here, you can reinstall macOS or perform a clean installation.
If you want a clean install:
- Select Disk Utility
- Click Continue
- Choose your internal Mac drive (usually named Macintosh HD)
- Click Erase
- Format as:
- APFS (for modern macOS)
- Mac OS Extended (Journaled) for older versions
- Close Disk Utility after erasing
Now return to the main recovery screen:
- Select Install macOS
- Click Continue
- Choose your internal drive
- Follow the on-screen instructions
The installation process will begin. Your Mac may restart several times — this is normal. Do not remove the USB until setup finishes.
Once installation completes, you’ll see the macOS welcome screen where you can create your user account and start using your Mac again.
Final Words
That’s it — you’ve successfully created a macOS bootable USB on a Windows PC and used it to install macOS on your Mac. Even without access to another Mac, you can fully recover, upgrade, or reinstall your system using this method.
This bootable USB is useful for:
- Fixing a Mac that won’t start
- Performing a clean macOS installation
- Upgrading to a newer macOS version
- Troubleshooting system errors
- Reinstalling macOS anytime without internet recovery
If you ever run into Mac startup problems again, just keep this USB safe — it can save you a lot of time and stress.
Good luck with your macOS installation, and enjoy your refreshed Mac!
