If you're still using a Mac OS X the time will come when your computer won't boot, or a problem may arise where you can't take control of the device, and booting from an OS X installation media will be required.
With the target Mac you want to upgrade turned off, connect your external drive. When turning on the Mac, hold down the Option key on the connected keyboard to bring up the Startup Manager. How to Install macOS From USB Choosing a USB Flash Drive for Installing macOS. USB flash drives are cheaper than ever, so you won't have to spend much. Formatting Your USB Flash Drive. You can only create a bootable installer for macOS on a Mac. If you're using a flash. Downloading the macOS. Dec 04, 2020 Plug the bootable installer into a Mac that is connected to the internet and compatible with the version of macOS you're installing. Press and hold the Option (Alt) ⌥ key immediately after turning on or restarting your Mac. Release the Option key when you see a dark screen showing your bootable volumes.
This is why it's recommended that you make a Mac OS X bootable USB when your Mac is in working conditions. However, if you find yourself on a scenario where your device (iMac, MacBook Pro, Air, Mac Pro or Mini) is not responding and you happen to have a Windows 10 device, then you can still be able to make a USB bootable installation media for your Mac OS X to reinstall the operating system using the Recovery Assistant.
These instructions will also work for Windows users who are running Mac OS X on a virtual machine and need to upgrade to the latest version. For instance, to OS X Yosemite.
Requirements
Before you dive into this guide, you'll need a few things:
- A broken Mac computer with Mac OS X.
- A trial copy of the TransMac software.
- One high quality USB flash drive with 16GB of storage.
- A copy of Apple's macOS (DMG file).
Now that you have all the necessary ingredients, you're ready to make a Mac OS X bootable USB using the DMG file of the operating system with the steps below.
Create Mac OS X bootable USB installation media
Before you can use TransMac, you first need to partition your USB flash drive with a GPT partition, as a normal MBR partition may not work. To do this, you'll need to use the Diskpart command-line utility on Windows 10.
Setting up GPT partition
Use these steps to set up a USB drive with a GPT partition:
Open Start on Windows 10.
Search for Command Prompt, right-click the top result and select the Run as Administrator option.
Type the following command to open Diskpart and press Enter:
Type the following command to determine the USB flash drive and press Enter:
Type the following command to select the storage and press Enter:
Quick tip: Theselect disk 1command as an example, but you have to replace 1 with the number of the flash drive you want to use.Type the following commands to delete everything from the USB thumb drive and press Enter:
Type the following command to convert the drive into a GPT partition and press Enter:
Type the following command to select the new partition and press Enter:
After you complete the steps, the USB flash drive from MBR to GPT format, you can use the steps below to create a bootable USB installation media to install Mac OS X.
Create USB install media
Use these steps to create a bootable media to install Mac OS X:
Download and install a copy of TransMac.
Quick note: TransMac is a paid software, but it has a 15-day trial solution, that give us more than enough time to move the DMG files to the USB drive from Windows. (If you want to support the developer, you can purchase the full version.)Insert the USB drive that you'll use to fix your installation of OS X. (Remember that all the data in the USB will be erased. Make sure you take off any important documents.)
Right-click the TransMac software icon and Run as administrator. (You'll be prompted to Enter Key or Run, because we'll be using it once, click the Run option.)
On the left pane, you'll see all the Windows PC drives listed, right-click the USB drive that you're intending to use to reinstall Apple's OS X and select the Restore with Disk Image option.
In the warning dialog box, click the Yes button.
Use the Restore Disk Image to Drive dialog box to browse for the DMG file with the installation files for Mac OS X Yosemite in this case, and click the OK button to create a bootable USB of the operating system.
Now, you'll have to wait a long time. No kidding. It could take one or two hours to complete the process depending on your computer and other variables.
Once your bootable USB installation media is ready, remove it and insert it into your Mac, power it on, holding down the Option key, and select the USB you just created to reinstall Mac OS X.
Installing Mac Os With Usb Ports
If you're having issues trying to create a bootable media, you can get a USB flash drive that comes with Mac OSX ready to install.
Ever since the release of Mac OS Lion the software upgrades for Macintosh computers are distributed through the online app store. 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 okay 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 bootable macOS offline installation disk is the only solution in such scenarios.
Install Mac Os With Usb Drive
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.
- First, download a copy of Disk Maker from the official website.
- 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.
- I use an MacBook Pro with High Sierra. Hence, I'm downloading disk maker X 7.
- The next step is to download full macOS installer from the App Store to your Applications folder.
- Run Disk Maker DMG installer and copy the app to the Applications.
- 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.
- Next is setting the USB pen drive for creating the bootable installer. Choose the third option ' An 8 GB USB Thumb drive.'
- The app will list all drives in your system. Pick the one you would like use as macOS USB installer.
- Ignore the warning message and proceed to Erase and Create macOS USB disk. Don't forget to provide your admin password when it prompts.
- 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.
- That's your backup. Unmount and keep the USB installer to a safe place.
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 Mac OS 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 Mac OS X bootable USB installation media
Before you can use TransMac, you first need to partition your USB flash drive with a GPT partition, as a normal MBR partition may not work. To do this, you'll need to use the Diskpart command-line utility on Windows 10.
Setting up GPT partition
Use these steps to set up a USB drive with a GPT partition:
Open Start on Windows 10.
Search for Command Prompt, right-click the top result and select the Run as Administrator option.
Type the following command to open Diskpart and press Enter:
Type the following command to determine the USB flash drive and press Enter:
Type the following command to select the storage and press Enter:
Quick tip: Theselect disk 1command as an example, but you have to replace 1 with the number of the flash drive you want to use.Type the following commands to delete everything from the USB thumb drive and press Enter:
Type the following command to convert the drive into a GPT partition and press Enter:
Type the following command to select the new partition and press Enter:
After you complete the steps, the USB flash drive from MBR to GPT format, you can use the steps below to create a bootable USB installation media to install Mac OS X.
Create USB install media
Use these steps to create a bootable media to install Mac OS X:
Download and install a copy of TransMac.
Quick note: TransMac is a paid software, but it has a 15-day trial solution, that give us more than enough time to move the DMG files to the USB drive from Windows. (If you want to support the developer, you can purchase the full version.)Insert the USB drive that you'll use to fix your installation of OS X. (Remember that all the data in the USB will be erased. Make sure you take off any important documents.)
Right-click the TransMac software icon and Run as administrator. (You'll be prompted to Enter Key or Run, because we'll be using it once, click the Run option.)
On the left pane, you'll see all the Windows PC drives listed, right-click the USB drive that you're intending to use to reinstall Apple's OS X and select the Restore with Disk Image option.
In the warning dialog box, click the Yes button.
Use the Restore Disk Image to Drive dialog box to browse for the DMG file with the installation files for Mac OS X Yosemite in this case, and click the OK button to create a bootable USB of the operating system.
Now, you'll have to wait a long time. No kidding. It could take one or two hours to complete the process depending on your computer and other variables.
Once your bootable USB installation media is ready, remove it and insert it into your Mac, power it on, holding down the Option key, and select the USB you just created to reinstall Mac OS X.
Installing Mac Os With Usb Ports
If you're having issues trying to create a bootable media, you can get a USB flash drive that comes with Mac OSX ready to install.
Ever since the release of Mac OS Lion the software upgrades for Macintosh computers are distributed through the online app store. 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 okay 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 bootable macOS offline installation disk is the only solution in such scenarios.
Install Mac Os With Usb Drive
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.
- First, download a copy of Disk Maker from the official website.
- 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.
- I use an MacBook Pro with High Sierra. Hence, I'm downloading disk maker X 7.
- The next step is to download full macOS installer from the App Store to your Applications folder.
- Run Disk Maker DMG installer and copy the app to the Applications.
- 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.
- Next is setting the USB pen drive for creating the bootable installer. Choose the third option ' An 8 GB USB Thumb drive.'
- The app will list all drives in your system. Pick the one you would like use as macOS USB installer.
- Ignore the warning message and proceed to Erase and Create macOS USB disk. Don't forget to provide your admin password when it prompts.
- 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.
- That's your backup. Unmount and keep the USB installer to a safe place.
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 Mac OS 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.
Pick the USB drive with the label 'Install macOS Mojave or High Sierra' 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.
