1. Sep 14, 2015  How to start up your Mac from an external USB storage device. Step 1: Open the System Preferences application in the Dock. Step 2: Now click the Startup Disk pane. You will be presented with various disk icons. Step 3: Select the system you would like to use to start your computer.
2. May 02, 2019 Purchase a FireWire flash drive or a hard drive with a FireWire interface and the appropriate connector cable, and then install a Mac operating system to allow the Mac computer to boot from that FireWire device. You can also use another Macintosh computer as a FireWire drive, provided that it has the appropriate FireWire connector.

• Mac Os High Sierra
• Boot Mac Os From Thumb Drive
• Boot Mac From Thumb Drive

If you have more than one Mac you want to upgrade to macOS 10.15 Catalina but don't want to waste so much bandwidth downloading it for each machine, one option is to create a bootable installer on a spare USB flash drive. Here's how to do it with the Terminal.

Apr 06, 2020 By default, your Mac starts up from its built-in hard disk, but a startup disk can be any storage device that contains an operating system compatible with your Mac. For example, if you install macOS on an internal or external drive, your Mac can recognize that drive as a startup disk. You can then follow the steps in this article to start up. Option 1: Put a full bootable Lion installation on the USB Drive with a recovery partition. What you need: an 8G thumb drive and OS X Lion from the App Store. What you get: A USB stick you can boot off and repair your Lion installation from. Download the Lion installer from Apple App Store.

One of the problems with the release of a major operating system update like macOS Catalina is the amount of times it has to be downloaded. As Apple usually intends each Mac or MacBook needing to be updated to download it, the process isn't really efficient enough for instances where many Mac desktops need the upgrade, like in a school or business if there isn't device management or macOS Content Caching for whatever the reason.

The strain could also be felt by users who own multiple Macs but also have a limited data allowance from their Internet provider, or a small amount of bandwidth that could make updating multiple machines take a very long time and saturate the available connection.

While in the olden days it was possible to get the software update on physical media, Apple doesn't offer that option anymore. However, it is still possible to create your own media, such as a spare USB thumb drive, that can do the same job.

Mac Os High Sierra

The first hurdle is to actually get the macOS Catalina installer onto a Mac. This is an unavoidable part of the process and will require just over 8 gigabytes of drive capacity to store.

Go to the Mac App Store and search for Catalina using the search bar, then click on View next to the macOS Catalina listing. Alternately, open the Mac App Store Preview page for macOS Catalina here then select View in Mac App Store.

Click on Get. This will load up the Software Update utility, which will ask if you want to download macOS Catalina. Click Download.

After the download has finished, macOS will automatically start the installer. Press Command-Q to quit the installer before it continues, as the update will be deleted upon installation.

Creating the Bootable Drive

You need an external drive to turn into a bootable version, and since it needs to be portable, your best choice is a USB thumb drive with a capacity of 16GB or more. Be aware that the drive will be wiped as part of the process, so ensure there isn't any precious data on the drive that could be lost if it isn't backed up elsewhere.

Connect the external drive to your Mac, and make a note of the external drive's name as it appears within macOS. This is important, as using the wrong name could lead to another connected drive being wiped by mistake.

Open Terminal within the Utilities folder within the Applications folder and enter in the following command by copying and pasting it directly into the window. Make sure to change the element titled 'USBdrive' for the name of the drive you intend to become the bootable installer.

Once pasted and corrected, press enter, then enter your password for macOS and press enter again.

Terminal will then warn of the USB drive being wiped as part of the process. Type 'Y' and press enter. Leave the Mac alone as it formats and copies over the installer.

Once Terminal says 'Install media now available,' it is safe to right-click the removable drive on the desktop renamed 'Install macOS Catalina' and select the 'Eject' command. It is now safe to remove the drive from the Mac.

Upgrading another Mac

Before proceeding, ensure there are adequate backups available for the Mac you are about to upgrade before the process starts.

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.

The Startup Manager is used to boot from a different drive from the default. In this case, select 'Install macOS Catalina.'

The Mac will then bring up a macOS Utilities window. To perform a straight update, select 'Install macOS' and follow the prompts.

The macOS Utilities menu also allows you to erase the Mac's drive, which you can optionally do if you do not wish to save any of the data and want a completely clean slate for the installation.

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Here are three different ways to put Lion on a USB thumb drive. If you buy and install Lion from the App Store  it downloads all 3Gigabytes from the App Store, installs Lion, then deletes the installer!  So when you go to install it on another machine it needs another 3Gigabyte download! Here’s how to make a re-usable installer.

Option 1: Put a full bootable Lion installation on the USB Drive with a recovery partition.

What you need: an 8G thumb drive and OS X Lion from the App Store.

What you get: A USB stick you can boot off and repair your Lion installation from.

Download the Lion installer from Apple App Store. DO NOT INSTALL IT ONTO YOUR COMPUTER OR THE INSTALLER WILL DELETE ITSELF. MAKE A COPY OF THE INSTALLER. Â If you have already installed it and it has deleted itself, Â go back into the App store and click on ‘purchases’ and next to Lion it will say ‘Installed’. Now option-click on ‘purchases’ and ‘installed’ will change to ‘install’ so that you can re-download the installer.

Format your Thumbdrive using a GUID Partition Table, and ‘ Mac OS Extended (Journaled)’, then you can run the Lion installer and install Lion onto the thumb drive.

More info here:Â http://support.apple.com/kb/HT4718

Option 2: Create a Lion Recovery Disk.

You’ll only need a 4G USB Drive for this option.

What you get: A USB stick you can repair your Lion installation from, but not run Lion from.

If your Macintosh has an existing Lion Recovery partition (this will be the case if Lion came pre-installed on your machine when you purchased your computer from Apple), you can use this method. It will not be a fill installer but it will use the internet to install Lion onto another computer. It involves downloading a program from apple called ‘Lion Recovery Disk Assistant’

Boot Mac Os From Thumb Drive

More info here:Â http://support.apple.com/kb/DL1433

To test if you have a Lion recovery partition, Just hold down Command-R during startup and Lion will give you the option of going into recovery mode if the recovery partition is there.

Option 3: Make a Lion Installation USB Thumb drive like the one you buy from Apple.

What you get: A USB stick you can install Lion from – like the one that comes from Apple.

You’ll need an 8G USB thumbdrive.

1. Purchase and download the Lion Installer via the App store as in Option 1 above.

2. Right-click on the installer and select “Show Package Contents” and find  the file called  “InstallESD.dmg” in the SharedSupport folder.

3. Use Disk Utility to ‘Restore’ this dmg file to a thumb drive to make a Lion Installation USB drive like you buy from the Apple Store. (the thumb drive must first be formatted as Mac OS Extended (Journaled) with GUID Partition Table.)

Boot Mac From Thumb Drive

More info on this here.