Install New Operating System Mac

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If you have an iMac Pro or Mac Pro with 128GB of memory (RAM) or more, your startup disk needs at least as much free storage space as your Mac has memory. 2 An external USB flash drive with a storage capacity of 16GB or more, unless you're using a Mac that doesn't need a flash drive to install Windows. Try to do this the night before you install the new operating system, as the install will be able to format the disk much faster. This is especially true if you have an IDE disk that is over 40 gigabytes, or Serial ATA (SATA) disk that is over 500 gigabytes.

What you need to install Windows 10 on Mac

  • MacBook introduced in 2015 or later
  • MacBook Air introduced in 2012 or later
  • MacBook Pro introduced in 2012 or later
  • Mac mini introduced in 2012 or later
  • iMac introduced in 2012 or later1
  • iMac Pro (all models)
  • Mac Pro introduced in 2013 or later

Install New Mac Operating System

The latest macOS updates, which can include updates to Boot Camp Assistant. You will use Boot Camp Assistant to install Windows 10.

64GB or more free storage space on your Mac startup disk:

  • Your Mac can have as little as 64GB of free storage space, but at least 128GB of free storage space provides the best experience. Automatic Windows updates require that much space or more.
  • If you have an iMac Pro or Mac Pro with 128GB of memory (RAM) or more, your startup disk needs at least as much free storage space as your Mac has memory.2

An external USB flash drive with a storage capacity of 16GB or more, unless you're using a Mac that doesn't need a flash drive to install Windows.

A 64-bit version of Windows 10 Home or Windows 10 Pro on a disk image (ISO) or other installation media. If installing Windows on your Mac for the first time, this must be a full version of Windows, not an upgrade.

  • If your copy of Windows came on a USB flash drive, or you have a Windows product key and no installation disc, download a Windows 10 disk image from Microsoft.
  • If your copy of Windows came on a DVD, you might need to create a disk image of that DVD.

How to install Windows 10 on Mac

To install Windows, use Boot Camp Assistant, which is included with your Mac.

1. Check your Secure Boot setting

Learn how to check your Secure Boot setting. The default Secure Boot setting is Full Security. If you changed it to No Security, change it back to Full Security before installing Windows. After installing Windows, you can use any Secure Boot setting without affecting your ability to start up from Windows.

2. Use Boot Camp Assistant to create a Windows partition

Open Boot Camp Assistant, which is in the Utilities folder of your Applications folder. Follow the onscreen instructions.

  • If you're asked to insert a USB drive, plug your USB flash drive into your Mac. Boot Camp Assistant will use it to create a bootable USB drive for Windows installation.
  • When Boot Camp Assistant asks you to set the size of the Windows partition, remember the minimum storage-space requirements in the previous section. Set a partition size that meets your needs, because you can't change its size later.

3. Format the Windows (BOOTCAMP) partition

When Boot Camp Assistant finishes, your Mac restarts to the Windows installer. If the installer asks where to install Windows, select the BOOTCAMP partition and click Format. In most cases, the installer selects and formats the BOOTCAMP partition automatically.

4. Install Windows

Unplug any external devices that aren't necessary during installation. Then click Next and follow the onscreen instructions to begin installing Windows.

5. Use the Boot Camp installer in Windows

After Windows installation completes, your Mac starts up in Windows and opens a ”Welcome to the Boot Camp installer” window. Follow the onscreen instructions to install Boot Camp and Windows support software (drivers). You will be asked to restart when done.

Mac
  • If the Boot Camp installer never opens, open the Boot Camp installer manually and use it to complete Boot Camp installation.
  • If you have an external display connected to a Thunderbolt 3 port on your Mac, the display will be blank (black, gray, or blue) for up to 2 minutes during installation.

How to switch between Windows and macOS

Restart, then press and hold the Option (or Alt) ⌥ key during startup to switch between Windows and macOS.

Learn more

If you have one of these Intel-based Mac models using OS X El Capitan or later, you don't need a USB flash drive to install Windows:

Install Operating System Mac New Hard Drive

  • MacBook introduced in 2015 or later
  • MacBook Air introduced in 2017 or later3
  • MacBook Pro introduced in 2015 or later3
Install fresh operating system mac
  • iMac introduced in 2015 or later
  • iMac Pro (all models)
  • Mac Pro introduced in late 2013 or later

To remove Windows from your Mac, use Boot Camp Assistant, not any other utility.

For more information about using Windows on your Mac, open Boot Camp Assistant and click the Open Boot Camp Help button.

1. If you're using an iMac (Retina 5K, 27-inch, Late 2014) or iMac (27-inch, Late 2013) or iMac (27-inch, Late 2012) with a 3TB hard drive and macOS Mojave or later, learn about an alert you might see during installation.

2. For example, if your Mac has 128GB of memory, its startup disk must have at least 128GB of storage space available for Windows. To see how much memory your Mac has, choose Apple menu  > About This Mac. To see how much storage space is available, click the Storage tab in the same window.

3. These Mac models were offered with 128GB hard drives as an option. Apple recommends 256GB or larger hard drives so that you can create a Boot Camp partition of at least 128GB.

Many people remember Mac OS X 10.6.8 fondly. Not just 10.6 Snow Leopard, but particularly its very mature 10.6.8 release, the final one in that series. It’s considered a stable and perfectly fine version. It’s not a problem—until they want to mitgrate to a newer computer with the same files, preferences, users, and other elements as their current one. That’s particularly true when they want to keep their system and essentially brain transplant it to the latest two updates, macOS Catalina and Big Sur, and find there’s no direct path.

Apple offers Migration Assistant both when setting up a Mac (whether new or erased) and as an app within macOS, particularly to migrate user accounts and applications. As a source, you can use a Time Machine backup, a disk image copy of your macOS startup volume (via a cloning app, for instance), or another Mac.

But Migration Assistant has its limits: in Catalina and Big Sur, you must migrate from a backup made from or a computer running Mac OS X 10.11 El Capitan or later. Attempts to copy from older installations lead to an error.

However, you’re not stuck. You have several alternatives you can try.

Install New Operating System Mac

Upgrade past 10.6.8

It may seem like a pain, but if you have a computer that can be upgraded to 10.11 El Capitan or later, that’s your best bet. This list of models from One World Computing will help you figure out if your Mac can be upgraded that far. It covers years of Mac releases. (No Macs that can run Snow Leopard can be upgraded to Catalina or Big Sur, which would solve the problem, too.)

Apple has instructions on installing a terminal release of Mac OS X or macOS for its old computers.

Once upgraded to El Capitan or later, you can then run Migration Assistant to transfer data to Catalina or Big Sur.

If your computer’s last OS option isn’t El Capitan, read on.

Copy just the user directory

When spanning such a long gap between releases, you may not need applications or any settings files—you just want to transfer all your document, pictures, and other personal files. In that case, you can use these directions in a Mac 911 column from last year. While that article was written to help you overcome a Migration Assistant failure, it also works when Migration Assistant can’t.

Each of the techniques in that article lets you move the files you need over to a new Mac. The options vary by what your older system is capable of and the level of technical detail you want to cope with.

Mac

Install an older Mac OS on an external drive for migration

Install New Operating System Mac 10

If the Mac you’re upgrading to (not from) is in the right range of vintages, you can do the following:

  1. Install Mac OS X 10.11 El Capitan on an external drive. (Download El Capitan from Apple’s site.) El Capitan seems to be the last release that can migrate files from Snow Leopard.
  2. Use the Startup Disk preference pane to select that external drive and restart.
  3. Use Migration Assistant during setup or after setting up on the external drive to transfer data from your Snow Leopard Mac.
  4. Use Startup Disk to restart with your newer Mac’s intended startup volume.
  5. Now run Migration Assistant pointing to the external drive.

If you don’t own a Mac that can install El Capitan, you might be able to borrow such a machine from someone and use the same external drive approach that won’t affect the startup drive of their system.

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

Ask Mac 911

We’ve compiled a list of the questions we get asked most frequently along with answers and links to columns: read our super FAQ to see if your question is covered. If not, we’re always looking for new problems to solve! Email yours to mac911@macworld.comincluding screen captures as appropriate, and whether you want your full name used. Not every question will be answered, we don’t reply to email, and we cannot provide direct troubleshooting advice.