Install Windows on your older Mac using Boot Camp
You need an external USB drive to install Windows on older Mac computers. To find out whether you have a Mac that requires an external USB drive, see the “Learn more” section in the Apple Support article Install Windows 10 on your Mac with Boot Camp Assistant. If your Mac is a newer model that doesn’t require a USB drive, follow the instructions in Install Windows on your newer Mac using Boot Camp instead.
What you need
The keyboard and mouse or trackpad that came with your Mac. (If they aren’t available, use a USB keyboard and mouse.)
A blank 16 GB or larger external USB 2 flash drive, formatted as MS-DOS (FAT).
To format an external USB drive as MS-DOS (FAT), use Disk Utility, located in /Applications/Utilities. In Disk Utility, choose View > All Devices, select the USB drive in the sidebar, then click Erase in the toolbar. In the dialog, enter a name for the drive, choose MS-DOS (FAT) from the Format pop-up menu, choose Master Boot Record from the Scheme pop-up menu, then click Erase.
A full-installation, 64-bit version of Windows 10 on a disk image (ISO file) or other installation media.
Sufficient free storage space on your startup drive. For information about the amount of free space needed, see the Apple Support Article Install Windows 10 on your Mac with Boot Camp Assistant.
Before you begin
Before you install Windows, make sure you back up important files.
Perform the installation
Do the following steps in order.
Step 1: Check for software updates
Before you install Windows, install all macOS updates.
On your Mac, log in as an administrator, quit all open apps, then log out any other users.
Choose Apple menu > System Preferences, click Software Update, then install all available updates.
If your Mac restarts after installing an update, open Software Update again to install any additional updates.
Step 2: Prepare your Mac for Windows
Boot Camp Assistant prepares your Mac by creating a new partition for Windows named BOOTCAMP and downloading the Boot Camp support software.
Important: If you’re using a portable Mac, connect it to a power source before continuing.
Connect an external USB drive or insert a flash drive into the USB port on your Mac; keep it connected or inserted while you install Windows and the Windows support software.
On your Mac, open Boot Camp Assistant , located in /Applications/Utilities.
At the introduction screen, click Continue.
The system is checked for total available disk space. Older Time Machine snapshots and cached iCloud files are removed to make space for Boot Camp. This process may take a long time to complete (you can click the Stop button to skip this process).
At the Select Tasks step, select all the tasks, then click Continue.
At the Create Bootable USB Drive for Windows Installation step, choose the Windows ISO image and the USB drive, then click Continue.
The Windows files are copied to the USB drive. This process may take a long time to complete (you can click the Stop button to interrupt this process).
At the Create a Partition for Windows step, specify a partition size by dragging the divider between the macOS and Windows partitions. If you have multiple internal hard drives, you can select a different hard drive from the one running macOS and create a single partition on that drive to use solely for Windows.
Important: You can’t resize the partition later.
When this step is complete, the Windows installer starts.
Step 3: Install Windows
In the Windows installer, follow the onscreen instructions.
When you’re asked where to install Windows, select the BOOTCAMP partition (you may need to scroll through the list of partitions to see it), then click Next.
WARNING: Do not create or delete a partition, or select any other partition. Doing so may delete the entire contents of your macOS partition.
Continue following the onscreen instructions to finish installing Windows.
After you install the Windows software, your Mac automatically restarts using Windows.
Follow the onscreen instructions to set up Windows.
Step 4: Install Boot Camp on Windows
After installing Windows, Boot Camp drivers that support your Mac hardware start installing.
Note: If the support software doesn’t install automatically, you need to install it manually. For instructions, see the Apple Support article If the Boot Camp installer doesn't open after using Boot Camp Assistant.
In the Boot Camp installer in Windows, follow the onscreen instructions.
Important: Do not click the Cancel button in any of the installer dialogs.
If a message appears that says the software you’re installing has not passed Windows Logo testing, click Continue Anyway.
You don’t need to respond to installer dialogs that appear only briefly during installation, but if a dialog asks you to install device software, click Install.
If nothing appears to be happening, there may be a hidden window that you must respond to. Look behind open windows.
When the installation is complete, click Finish, then click Yes to restart your Mac.
After your Mac restarts, follow the instructions for any other installers that appear.