If your Mac suddenly refuses to boot up properly, you might need a bootable macOS USB installer to make repairs. But how do you create such a disk if all you're left with is a Windows 10 computer? Fortunately, there's a great tool that you can use for free to create bootable macOS media on a USB drive in a Windows 10 environment. This article shows you how to download a macOS DMG file, format a USB drive using a GUID Partition Table, burn the DMG to the drive and boot your Mac from the USB. All the steps except the last one are done on a Windows 10 machine.

Part 1: Download macOS or Mac OS X DMG File

The first step is to get the DMG disk image file for the version of macOS that you want. You can get a copy of the latest macOS version from Apple download portal or App Store here. There are also several other direct download sites that offer various versions of Mac OS X in DMG format rather than the standard APP format that runs on Mac. Since you're working in a Windows environment, you need the DMG rather than the APP file.

macOS DMG Download Link:

Part 2: Easily Create a Bootable macOS USB from Windows 10/8/7 PC

• For awareness, a pretty simple method to “temporarily revert” to Yosemite after loading El Capitan, is to use an external thunderbolt or USB drive, load Yosemite to it from another Mac running Yosemite, then plug it into the system you already installed El Capitan on, and use the Option key to select which device to boot from.
• Preparing Mac Device for the Installation of Mac OS X El Capitan Both Mavericks and Yosemite are easier to download and install on Mac devices, however, this is not the case with Mac OS X El Capitan.

After I physically install the SSD in the computer, how do I install the OS? I want to do a fresh install, but will there be a menu that asks me what I want to do with this new SSD, whether I want to import data from my old hard drive, or completely reinstall an OS? I think I will need a USB stick with the El Capitan installer, but how will I.

You have now formatted the partition of USB drive. It's time to download UUByte DMG Editor for Windows. Although this is a premium software, you can use the initial free trial period to create a bootable macOS USB on Windows 10. After installing the application, follow the sequence of steps shown below:

Install Mac Os X El Capitan On External Drive

Updates (Dec 8, 2020): The latest version of UUByte DMG Editor is able to format the USB automatically.

Step 1: Right-click the software icon on desktop and select 'Run as Administrator' from the contextual menu. Choose 'Run' when prompted.

Step 2: Insert your formatted USB drive, and click 'Burn' tab on the main screen.

Step 3: Click 'Browse' button to import macOS dmg file into the program. And select the USB drive name from the second row. You can also set a volume labe for that USB drive.

Step 4: Click 'Burn' button at the bottom to start the process. You will see a progress bar and wait around 10 minutes to get it done.

Step 5: Once the progress bar is at 100%, a bootable macOS USB is ready. After that, you can use that USB drive for installing macOS.

This is one of the easiest way to create a bootable macOS USB on a Windows PC. The steps are simple and instructions are pretty clear.

Part 3: Format USB Drive to GPT If Failed

If the USB drive created in above step was not seen as a bootable device on your Mac, then you need to take an addtional step before burning. That's formatting the USB to GPT.

Mostly, the USB drive was formmated to FAT32 in default when being shipped out from the factory. However, FAT32 can be only used for installing OS with legacy BISO, which doesn't work for macOS. So the next step is to format your USB drive in the GPT partition style in order to burn installation files to the desired USB drive. You can do this in Command Prompt as admin. In elevated Command Prompt (Ctrl+Shift+Enter), input the following series of commands followed by Enter after each line:
Diskpart
List disk
Select Disk X (X stands for the USB drive name that appears after the previous command)
Clean
Convert GPT
Create partition primary

Part 4: Boot Mac from macOS USB Drive for Installation

Install Mac Os El Capitan On External Drive Windows 7

Now remove the USB drive and insert it into the Mac computer. To boot from the disk, you need to hold down the option key when you hear the boot chime. This will take you to the Startup Disk Manager, where you should be able to see the USB drive. It might have a different name, but as long as it is bootable, you'll be able to see it there. Once you select it, the computer will boot from the disk and the macOS installation will begin.

Troubleshooting

Flashing Error: You might receive a flashing error message at the end of burning process. Please don'y worry and ignore this error. The USB becomes a bootable disk and you can use it to install macOS even this error pops up.

Mac Os Sierra

About Official EI Capitan DMG: There has a serious bug in the official release of OS X El Capitan, which contains .pkg installer only. The burning process will fail for sure. Please use this modified EI Capitan DMG file instead, which was approved a good option.

Reinstall Os X El Capitan

Registration Failed: Please make sure the computer is connected to Internet and no proxy or VPB is running during registration. If the problem still exists, please send an email to support team asking for a new code.

Conclusion

Mac Os El Capitan 10.11 Download

The whole process might look a bit complicated if this is your first time, but just follow the instructions in this article and you should be fine. That being said, you need to be careful when downloading the DMG file and formatting your USB drive. If you don't do these two steps correctly, the output drive from the UUByte DMG Editor software won't be bootable, which means you can't install macOS from that USB drive, and you may need to do the whole thing over again.