Apple does not officially distribute macOS Big Sur as an ISO file; they only provide the full installer app via the Mac App Store . To get a 2021-spec ISO for virtual machines (like VMware or VirtualBox) or Hackintosh builds, you must manually create it using a Mac and the Terminal.
| Issue | Fix | |-------|-----| | “createinstallmedia: command not found” | The installer is incomplete – re-download it. | | “Not enough space” | Use a 16GB DMG size or increase to 20GB. | | “Could not mount” | Run diskutil list and manually unmount any leftover volumes. | | ISO won't boot in VM | Ensure VM is set to . | macos big sur iso 2021
The represents the peak of Apple’s transition era—beautiful, stable, and powerful. While it no longer receives active development, it remains a valuable tool for virtualization, legacy hardware, and software compatibility testing. By creating your own ISO from Apple’s legitimate installer, you ensure security, integrity, and peace of mind. How to Create a macOS Big Sur ISO
Use the createinstallmedia tool on a Mac to convert the official App Store installer into a bootable ISO. For daily driving on real Macs: Upgrade to