Before you begin, make sure you have everything you need:
- An Intel-based Mac
- A Microsoft Windows installation media or disk image (ISO) containing a 64-bit version of Microsoft Windows 8 or later*
- An Apple keyboard, mouse, or trackpad, or a USB keyboard and mouse
- At least 55 GB of free disk space on your startup drive
- For most Mac models, you also need a blank 16 GB or larger USB flash drive
You don't need a USB flash drive for MacBook Pro (Retina, 13-inch, Early 2015), MacBook Pro (Retina, 15-inch, Mid 2015), MacBook Air (13-inch, Early 2015), iMac (Retina 4K, 21.5-inch, Late 2015), iMac (21.5-inch, Late 2015), iMac (Retina 5K, 27-inch, Late 2015), iMac (Retina 5K, 27-inch, Mid 2015), and Mac Pro (Late 2013). These models use the internal drive to temporarily store what you need to install Windows.
*Read more about system requirements to find out whether your Mac supports installing a specific version of Windows, or to learn about installing older versions of Windows. If you're installing Windows for the first time, use a full installation (not an upgrade) disc or disk image.
Check System Requirements
Some versions of Windows require a certain processor, and more hard drive space and memory (RAM) than others. Check the documentation that came with your copy of Windows to find out what you need. Then use System Information to see what your Mac currently has.
Get a Windows disk image
When you purchase Windows, it comes as a disk image file (ISO) that you download, or as an installation disc or USB flash drive. If your copy of Windows came on a DVD, you might need to create a disk image of it to work with Boot Camp. If your version of Windows came on a USB flash drive, you can download an ISO from Microsoft.
Open Boot Camp Assistant
Boot Camp Assistant guides you through installing Windows on your Mac. Open this app from the Utilities folder in the Applications folder and follow the onscreen instructions to automatically repartition your startup disk and download related software drivers for Windows. If you're prompted during installation, connect a blank USB flash drive.
Format your Windows partition
When you complete the assistant, your Mac restarts to the Windows installer. When you're asked where you want to install Windows, select the BOOTCAMP partition, then click Format.
Follow the onscreen prompts to finish your Windows installation.
Restart your computer
After Windows is installed, you can switch between OS X and Windows. Use the Startup Disk preference pane in OS X, or the Boot Camp system tray item in Windows to select your startup disk, then restart your computer.
For more information about using Windows on your Mac, click the Open Boot Camp Help button in Boot Camp Assistant. These resources also contain helpful information: