Macbooks or iMacs hardly require reinstallation of their Mac OS, but when they do then it’s a fairly difficult process especially if your secondary computer is Windows. Reinstalling Mac OS is a time-consuming process and requires a lot of patience that’s why recommend doing this process in your free time or weekends.

• In this tutorial and video walkthrough, I’ll show you how to create a bootable USB drive for OS X El Capitan in just a few easy steps Note: your USB flash drive must be at least 8GB in size. Ensure that there’s nothing on the drive that you wish to keep, as this process will completely erase the drive including any volumes.
• Bootable USB Installers for OS X Mavericks, Yosemite, El Capitan, and Sierra First, review this introductory article: Create a bootable installer for macOS. Second, see this How To outline for creating a bootable El Capitan installer.

Step 6: Click on Erase button then create the disk. You now have an OS X 10.11 El Capitan installer in a bootable USB. Use Terminal to Create the El Capitan Bootable USB Installer. Follow these steps to create a bootable USB installer of El Capitan in Terminal. Connect the USB flash drive to your Mac. Give the flash drive an appropriate name. You can do this by double-clicking the device's name on the desktop and then typing a new name. From this point, we've now provided plenty of installation files whether for installing macOS on Windows or on Mac. Such as macOS Sierra DMG, macOS High.

To get started with you require a USB drive with at least 8GB storage (16GB recommended). Then you need a working Mac OS ISO or DMG Installation Image. You can download it from the Apps Store or you can find Mac OS Image at ISORIVER.

There are 2 Methods to Create a Bootable USB drive of Mac OS on your Windows PC.

Method 1: Using TransMac

1. Download TransMac’s latest version for Windows from this link.
2. Connect your USB drive
3. Right Click on your USB drive option in TransMac and select Format Disk for Mac
4. After that, right-click the USB Drive and select Restore with Disk Image
5. Point to your Mac OS .dmg or .iso file by clicking the add button.
6. After that TransMac will create bootable Mac OS USB within few minutes.
7. Then you can insert it into your Mac, hold down the option key while turn on and boot your system with this USB.

Method 2: Using PowerISO

Another disk image utility that you can use is PowerISO. It can be used for burning both ISO files and DMG files to USB to create a bootable drive. Follow the steps below to Create a Bootable Mac OS USB on Windows PC.

Step 1: Firstly Download PowerISO and install it in your Windows PC. Launch the app and insert a USB drive into your computer.

Step 2: Import the DMG / ISO file directly by clicking on ‘Burn’ in the toolbar.

Step 3: In the Burn window, select the DMG / ISO file from the Source File section.

Step 4: You can modify the settings to adjust burn speed. The default will be set to the maximum, so you can reduce that.

Step 5: You can choose to finalize the disk and verify it. Any errors in the bootable USB will show up at that point.

Step 6: Now click on “Burn” and wait for the progress bar to reach 100%.

After the successful creation of Bootable Mac OS USB, boot your Macbook from this USB drive by clicking the option button during bootup and select this USB drive.

Watch this Video Tutorial

That’s it for the tutorial If you face any issues or had any query then please let us know in the comment section below. You can also send us an email via the contact us page for personalized support.

Customers get Software upgrades for Mac computers through the online app store ever since the release of macOS Lion. Be it a clean install or upgrade, Mac App store require you connect to the internet to download whole installation files. The online OS update is OK if you have stable broadband connectivity and enough bandwidth. Apple also provides an option for internet recovery of macOS if your computer fails to boot. But there are situations where you can’t download the OS from the Apple servers. Having a macOS offline installer or a bootable USB disk is the only solution in such scenarios.

Download macOS offline Installer

Installing macOS without internet requires a bootable USB disk. And you need to download a full-size macOS installer for making this disk. Hence, before anything, we will tell you how to download macOS offline installer directly from Apple to your Mac using a GitHub script.

Download the gibMacOS script from this link and extract it to your Mac. From the extracted folder, run the script called gibMacOS.command — it will open the Terminal as shown below.

Wait for the script to fetch the macOS download catalogue from Apple. When the list is ready choose a number as per your OS option and press the Return/Enter key. You can use this script to download macOS Big Sur (11.1), Catalina (10.15), Mojave (10.14), and High Sierra (10.13.6). A new folder “macOS downloads” appears in the “gibMacOS-master” as you provide a download option, and the OS starts downloading as you can see in the video.

Create Macos El Capitan Bootable Usb Drive

The OS gets downloaded as parts, PKGs, DMGs and other files. For macOS versions up-to Big Sur, you need to use another script “BuildmacOSInstallApp.command” in the main folder to join all the downloads and make the full macOS installer app. All you need is to drag and drop the downloaded macOS folder to the terminal window. The script will build the offline installer and save it to the same folder.

You don’t need to use the second script if your choice is macOS Big Sur. Because, for macOS Big Sur you get a full-size installer from Apple in PKG format. Double-click and open the InstallAssistant.PKG to save the “Install macOS Big Sur.app” to the Applications folder.

Bootable Flash Drive Creator

Apart from this, some older versions of macOS are available for direct download from Apple (Sierra, EL Capitan, Yosemite) in DMG format.

How to make a macOS bootable USB installer

It is possible to create a backup macOS installer on a DVD or USB drive but later is the best choice. Most of the Macs these days don’t have DVD slots, and the installation through a disc is very slow. Hence we discuss only about making macOS recovery installer on a USB disc. For this you need a Mac and a USB pen drive of at least 8 GB space, and a third-party app called DiskMaker.

Bootable El Capitan Installer

1. First, download a copy of Disk Maker from the official website.
2. Choose a version as per your requirement. For example, if you want make USB installer for macOS Catalina 10.15, download Disk Maker X 9.
3. I use an MacBook Pro with High Sierra. Hence, I’m downloading disk maker X 7.
4. The next step is to download full macOS installer from the App Store to your Applications folder.
5. Run Disk Maker DMG installer and copy the app to the Applications.
6. The application will automatically detect the downloaded macOS as shown in the screenshot. Select “Use this Copy” if you would like to proceed with it.
7. Next is setting the USB pen drive for creating the bootable installer. Choose the third option ” An 8 GB USB Thumb drive.”
8. The app will list all drives in your system. Pick the one you would like use as macOS USB installer.
9. Ignore the warning message and proceed to Erase and Create macOS USB disk. Don’t forget to provide your admin password when it prompts.
10. Keep checking notifications tab for progress. When it completes you will find Install macOS Mojave (or High Sierra) mounted to your desktop as a USB disk.
11. That’s your backup. Unmount and keep the USB installer to a safe place.

Create Macos El Capitan Boot Usb

Unfortunately, the above app is not compatible with macOS Big Sur 11 and above. Check the instructions on Apple website, the manual method to make macOS offline USB installer.

What is the alternative if I don’t have usable Mac at the moment?

This method is applicable when you have a Mac, and the internet recovery fails. But think about a situation when your only Mac stops to boot, and you don’t have USB installer or TimeMachine backup! Downloading MacOS DMG file might save you. If you have a macOS DMG, you can create bootable USB disk from a Windows PC — use a software like TransMac for this purpose.

Clean installing or restoring a Mac offline with USB pen drive

As said earlier, you could use the macOS USB installer to do a clean install or restore it upon a boot failure. Just connect the USB disk and press the Option/Alt Key when you hear the boot sound. The Mac will then display all the startup disks available.

Create Macos El Capitan Bootable Usb Using

Pick the USB drive starting with the label “Install macOS” and follow on-screen instructions to complete the installation. If you need, use the Disk Utility to format the drive for doing a clean install.