Open and format the drive as Mac OS Extended (Journaled) with a GUID Partition Map . Name the drive USB .
macOS Big Sur 11.2.1 Installer DMG: Download and Installation Guide Updated May 28, 2026
hdiutil create -o /tmp/BigSur -size 14000m -volname BigSur -layout SPUD -fs HFS+J Use code with caution. Mount the newly created blank image to your system: macos big sur 1121 installer dmg
package on Apple's servers or archived as a DMG/ISO for specific installation needs. Core Specifications Release Dates: Initially released February 9, 2021 (Build ); a revised version followed on February 15, 2021 (Build Full Installer Size: Approximately Update Size: for users already on Big Sur. Key Fixes and Features MacBook Pro Charging Fix:
: Reinstall the OS if your Mac experiences system corruption or cannot boot. Open and format the drive as Mac OS
Confirm the download. Once completed, the file named Install macOS Big Sur.app will sit in your /Applications directory. Method B: Using Terminal (Recommended)
: Supports MacBook (2015+), Air/Pro (2013+), Mac mini (2014+), and iMac (2014+). 🚀 How to Use the Installer Open the DMG : Double-click the file to mount it. Mount the newly created blank image to your
: The update plugged a significant security hole in Sudo , a 10-year-old vulnerability that could allow attackers to gain root access and take control of a Mac.
Use the createinstallmedia tool embedded inside Apple's official App bundle to flash the Big Sur setup files onto the mounted volume. You will need to enter your Mac's administrator password.
With the release of macOS 11 Big Sur, Apple ushered in a new era for its desktop operating system, introducing a redesigned interface, a new icon set, and a host of performance and security improvements. Among its significant updates, macOS Big Sur 11.2.1 stands out as a crucial release, particularly for fixing some critical bugs that impacted earlier versions. This guide is a comprehensive resource for understanding, downloading, and safely installing the macOS Big Sur 11.2.1 DMG installer.
Ensure you do not have any other disk images mounted, or restart your Mac to flush out frozen cached processes.