Restart Mac From Bootable Drive

Dec 21, 2020 • Filed to: Solve Mac Problems • Proven solutions

A Universal Serial Bus or USB drive, also known as a flash drive is a portable data storage device that includes a memory which includes a USB interface. It is typically removable and much smaller than an optical disc. Any sort of data can be stored in this device. The drives are available in various sizes and if we talk about storage, the 2TB(Tera-Byte) flash drives in terms of storage capacity are the largest ones available in the market.

The OS on my Mac recently stopped working and in order to fix the issue I needed to use a bootable USB drive to reinstall the OS. I'm going to take you thro. How to Create Bootable MacOS Sierra USB installer on Mac.

Today, these drives are one of the most consumed used devices in the world. Thanks to their portable nature, affordability, and compatibility, USB drives are being used to send and receive endless information across a surplus of networks and platforms all around the globe. This small tool has opened the world to a stream of limitless options for storing, transferring, copying data, and much more. One of them includes Booting the Mac from such a device.

Part 1. Reasons for Mac Boot from USB:

Booting the Mac from USB in a way gives the power back to the user. The likeliest of the reason for choosing the boot from the USB method is that your Mac won't start which denies the user access to the computer. Using an external source like the USB drive helps the user get around the problem. It provides the user access to the contents of the internal drive, assuming the data is safe and not corrupted. It also helps to repair the Mac disk with Disk Utility and other tools. Here are the top reasons why the user should choose to Boot Mac from USB:

  • Allows the user to install a different version of macOS.
  • It allows the user to test a new version before you decide to upgrade.
  • Allows risk-free testing of the Beta version.
  • Faster and efficient.
  • By installing older versions through USB, it permits certain Apps to run which are not compatible with the latest macOS.

Part 2. Preparations for Booting Mac from USB:

To ensure a risk-free procedure certain measure should be taken:

  • The user should buy a name-brand flash drive.
  • The USB should contain 16-32GB of free space.
  • The user should scan the flash drive with some reputable Anti-Virus software.
  • The user should check to see what size of ports they have on the Mac. A 12' Mac only contains a single C-Type port.
  • Make sure to purchase the C port flash drive to avoid any inconvenience.
  • It is recommended that the user should go with a USB 3.0 supported drive, with a size of 16GB to ensure a swift transfer of data.
  • The USB drive should be formatted with a supported GUID partition.
  • It should contain an OS X installer or a usable operating system to work with.

Part 3. How to Create Bootable USB on Mac:

There are a few general guidelines that can help get your machine started which are mentioned above, regardless of the OS the user prefers.

Here are the methods to create a bootable USB drive on Mac.

  • Creating a Bootable USB Using Terminal.
  • Create a Bootable drive with the help a third party compression software, which is available for free.

Creating a Bootable USB Using Terminal:

The terminal is the default gateway to the command line on a Mac. It is just like the Command Prompt feature works for MS Windows. The Terminal feature ensures a hassle-free experience for the Mac user without the conventional pointing and clicking, the user just has to type the commands and the computer does the rest. The user can find Terminal in the Applications>Utilities folder or it can be checked in the finder utility.

Using the Terminal feature is the most simple way to create the bootable USB drive. The user just needs to follow one easy step which is renaming the MyVolume portion of the command with the name of the drive. The name of the drive can be changed using the Disk Utility of Mac.

Here are the steps required after opening the Terminal feature to create a bootable USB drive.

  • Copy and paste the command which is suited for the version of the operating system into the Terminal window.
  • The command for macOS Mojave is as follows:

sudo /Applications/ --volume/Volumes/MyVolume

  • Press the Return key.
  • Enter the password.
  • Confirm to erase the USB drive by typing Y followed by the Return key.
  • The terminal will erase all the data inside the drive and create the bootable USB drive.

If there is a need to install a different version of the operating system then the user just has to replace the above-underlined command with their desired version of OS. For example, if the user wants to install Mac OS Sierra instead of Mojave then they would have to replace '' with '' inside the command line.

Part 4. How to Boot Mac from USB Media:

After creating a bootable USB drive, the user simply needs to plug the created drive into the open port on the Mac. Here are the steps to boot Mac from the USB flash drive:

  • Power on the system.
  • Press and hold the Option (Alt) key on the keyboard when the computer starts.
  • Select the USB drive as a startup disk when the option appears.
  • The system will start the boot process off the USB drive.
  • Install the operating system from the macOS utilities.
  • Data can be restored by using the Time-Machine backup option.

Part 5. How to Recover Data from Unbootable Mac:

The Mac becomes unbootable when the BIOS which is a firmware that is used to perform hardware initialization during the booting process fails to recognize the startup process. It usually happens when there is a failed system update, system crash, damaged MBR, or when the drive becomes corrupt.

Recoverit Mac Data Recovery tool is the most efficient option to recover all the lost data when Mac becomes unbootable. Developed by Wondershare, Recoverit is one of the most preferred recovery tools in the world. The tool provides an instant preview of what is recovered after a detailed scan. It allows you to connect almost every type of portable device and recover data from them. Data can be restored by performing the recovery and repair process. The process involves the installation of the Recoverit software that offers users the chance to get back the important data that they had lost.

First of all, the user is required to download the Recoverit software on the Mac system from the official website. Here are the following step required to recover data from an unbootable computer: Gmt to pst converter.

  • Installation: Please Install Recoverit by clicking on the icon.
  • Select the folder: Select the 'Recover from Crash Computer' option.
  • Initiate Recovery Process: Click on 'Start' for the recovery process to launch.
  • Create Bootable Drive: Select the 'Create USB bootable drive' option and click on 'Create'.
  • A pop up will appear that will prompt the user to format the USB drive.
  • Format the Drive: Click on 'Format' Now.
  • The process will start that will create a bootable flash drive.
  • Recover Data: After the boot is completed, click on the 'View Guide' option to recover data.
  • Start Recoverit: Launch the Recoverit software again.
  • Recover Data: Scan the drives for lost data.

All hope gets lost when the computer becomes unbootable and the data gets deleted. Recoverit recovery software is the most convenient program when it comes to retrieving lost data from the computer.


Installing the macOS from a USB flash drive gives the user an instant solution when the Mac installer due to some reason refused to work. The method to create a bootable drive is easier than it sounds. Now, you know what to do whenever you want to upgrade your macOS from a bootable external source by following different methods to ensure a safe and hassle-free process. If you lose valuable data when the Mac becomes unbootable then you can easily recover the lost files by using the Recoverit recovery software. Recoverit guarantees data recovery in no time.

Video Tutorial on How to Boot Mac into Recovery Mode

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Apple’s relatively new M1 Macs that rely on Apple silicon have a number of usability differences from previous Intel-based Macs. One difference that’s tripped some readers up is how to start up or boot the M1 Mac from an external drive. Intel Macs generally make this easy.

You might want to use a bootable external drive to have a higher-capacity SSD than is offered or affordable via Apple’s pricing. Or you want one for backup in case something goes very pear shaped with your M1 Mac.

Testing indicates that the following are required to start up from an external volume:

  • A Thunderbolt 3 drive. That’s not just one that uses the USB-C connector, but is a native USB 3.1 or 3.2 drive. Nor can you use a Type A adapter for a USB 3.0 or later drive. Success appears to require a native Thunderbolt 3 drive.

  • Erasing the drive completely, then formatting it as APFS.

  • Obtaining a Big Sur installer, and then installing Big Sur from your M1 Mac directly onto the external drive. (This will allow only an M1 Mac to boot from the drive; Intel Macs will be unable to start up from your M1-prepared external drive.)

Let’s expand on each point.

Thunderbolt 3 drive

Most inexpensive external drives use a flavor of USB 3 to connect over USB-C. Thunderbolt 3 is generally reserved for high-performance drives and arrays of drives used for graphics and video purposes. However, One World Computing offers a specific line of lower-cost, bus-powered Thunderbolt 3 SSDs. (Some people have apparently been able to get a USB 3 drive to work for this, but no one has narrowed down which ones or why, so it’s impossible to recommend it as a course of action.)

With an SSD inside, OWC charges $199 for 480GB and $299.75 for 1TB. You can purchase higher capacities, or just get its Envoy Express enclosure, which runs $79, to which you can add any SSD that’s designed for the 2280 M.2 NVMe standard. (That sounds like a mouthful, but you can search on that to find compatible SSDs.) OWC says it supports current capacities up to 4TB, and is designed to support future higher capacities, too. I opted to buy a relatively inexpensive 500GB SSD for now (about $75) so I could have a bootable option.

Erase and format as APFS

To use Big Sur, the drive has to be formatted as APFS. But reports indicate that you may not be able to just change the formatting on an existing drive, as invisible partitions used for purposes related to booting from an Intel drive from a previous macOS installation on the drive could cause issues. To avoid that, select the drive in Disk Utility, click Erase, and follow prompts to create a single APFS container. This should wipe out any conflicting data structures.

Obtain the Big Sur installer

Since you have to be running Big Sur on an M1 Mac, you should be able to download the installer directly from the Mac App Store via this link. Big Sur 11.1 or later is required.

Install Big Sur onto the external drive

Launch the Big Sur installer, and select the external drive as the target. Follow the prompts and steps. When your Mac restarts, it will boot from the external drive to complete the installation.

If you want to make this drive a bootable clone, Bombich Software, makers of Carbon Copy Cloner, recommends you first clone your data volume (which its software can do), and then install Big Sur after that.


Restart from your internal drive or switch between

To get back to your internal drive as the startup volume, you can open the Startup Disk preference pane while macOS is running on the external drive and select the internal drive. Then click Restart.

You’ll have to unmount the external drive after the restart is complete, and some people have reported that Big Sur says one of its partitions remains in use. (Catalina and Big Sur invisibly divide a macOS into a volume containing system files and a volume with your user data; the data volume may not unmount correctly.) You might prefer to shut down at that point, unplug the external drive, and start up again.

Create A Bootable Drive Mac

You can also use recovery mode to change the startup disk. This is a bit more complicated with an M1 Mac than an Intel one, where you could simply hold down the Option key while restarting and select a drive (unless you had turned on certain security settings, in which case you’d need to use recovery mode to disable them).

Here’s how you change the startup drive from recovery mode with an M1 Mac:

  1. If macOS is running, you need to shut down. A restart doesn’t work. Select  > Shut Down.

  2. When you see your Mac has powered down, hold down the power button until you see a prompt that says “Loading startup options.”

  3. When the Options icon appears, you will also see a list of volumes next to it that you can select. Select the volume that you want to start up from.

  4. Click Continue and the Mac restarts from that volume.

This Mac 911 article is in response to a question submitted by Macworld reader Gerald.

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