Mac users wishing to create a bootable install disk for Big Sur now need to use the createinstallmedia command in Terminal, and here’s how to do it. These instructions work to create a bootable install disk for all versions of macOS from macOS 11 Big Sur back to OS X El Capitan 10.11. I actually think the idea of a single, unified, development environment like what you're after is somewhat antithetical to OS X design principles. One of the great things I've found, since switching to OS X for development work about a year ago, is that many OS X application developers share my own personal philosophy when it comes to software.
The first Mac with Apple silicon will ship by the end of this year, which some people have assumed will an iPad-like ultralight MacBook, maybe a new 12-inch, and others have hoped would be an homage to the previous transition — either a MacBook Pro, iMac, or both. And, also just like before, the entire transition is expected to take 2 years.
To get the latest features and maintain the security, stability, compatibility, and performance of your Mac, it's important to keep your software up to date. Apple recommends that you always use the latest macOS that is compatible with your Mac.
Learn how to upgrade to macOS Big Sur, the latest version of macOS.
If a macOS installer can't be used on your Mac, the installer will let you know. For example, it might say that it's too old to be opened on this version of macOS, or that your Mac doesn't have enough free storage space for the installation.
To confirm compatibility before downloading, check the minimum requirements for macOS Catalina, Mojave, High Sierra, Sierra, El Capitan, or Yosemite. You can also find compatibility information on the product-ID page for MacBook Pro, MacBook Air, MacBook, iMac, Mac mini, or Mac Pro.
Before installing, it’s a good idea to back up your Mac. Time Machine makes it simple, and other backup methods are also available. Learn how to back up your Mac.
It takes time to download and install macOS, so make sure that you're plugged into AC power and have a reliable internet connection.
Safari uses these links to find the old installers in the App Store. After downloading from the App Store, the installer opens automatically.
Safari downloads the following older installers as a disk image named InstallOS.dmg or InstallMacOSX.dmg. Open the disk image, then open the .pkg installer inside the disk image. It installs an app named Install [Version Name]. Open that app from your Applications folder to begin installing the operating system.
Follow the onscreen instructions in the installer. It might be easiest to begin installation in the evening so that it can complete overnight, if needed.
If the installer asks for permission to install a helper tool, enter the administrator name and password that you use to log in to your Mac, then click Add Helper.
Please allow installation to complete without putting your Mac to sleep or closing its lid. Your Mac might restart, show a progress bar, or show a blank screen several times as it installs macOS and related firmware updates.
You might also be able to use macOS Recovery to reinstall the macOS you're using now, upgrade to the latest compatible macOS, or install the macOS that came with your Mac.