VirtualBox has notoriously poor macOS support. The 2021 Big Sur ISO works where newer ISOs fail because VirtualBox 6.1/7.0 relies on an outdated audio driver (HDA) that Apple removed in Monterey.
Terminal commands for VirtualBox (Host):
VBoxManage modifyvm "BigSur2021" --cpu-profile "Intel Core i7-6700K"
VBoxManage setextradata "BigSur2021" "VBoxInternal2/EfiGraphicsResolution" "1920x1080"
VBoxManage modifyvm "BigSur2021" --nested-hw-virt on
Boot the ISO. If you see a Guru Meditation error, your 2021 ISO is the only version that supports the -cpu-profile fallback.
Using a Mac (or Hackintosh), open Terminal and use the softwareupdate tool to fetch the historical version. Note: Apple hides old versions, so you may need to use the installinstallmacos.py Python script from Github (by grahamperrin).
Alternatively, if you have a legitimate copy from 2021:
# If the installer is in your Applications folder
ls -la /Applications/Install\ macOS\ Big\ Sur.app
macOS doesn’t boot from a standard El Torito ISO like Windows or Linux. The real installer uses a hybrid UEFI‑bootable image with an APFS or HFS+ filesystem. Converting the official Install macOS Big Sur.app to a bootable ISO requires hacky steps:
Result: Most community-made Big Sur ISOs from 2021 are either:
This is the downside of using a 2021 ISO in the current day:
If you need Big Sur on non‑Apple hardware:
| Method | Difficulty | Performance | Legality |
|--------|------------|-------------|----------|
| Official .app → VM (macOS host) | Easy | Native | ✅ Legal |
| InstallMacOSBigSur.dmg → VMware (Windows) via unlocker | Medium | Fair | ⚠️ Gray area (Apple EULA forbids non‑Apple hardware) |
| Hackintosh (OpenCore) with Big Sur | Hard | Excellent | ❌ EULA violation |
| Cloud macOS (MacStadium, Scaleway) | Easy | Great | ✅ Legal (but paid) |
The ISO route is the least reliable and most dangerous.
| 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 EFI (not BIOS/Legacy). |
As of 2025, Apple has moved on to macOS Sonoma and Sequoia. However, Big Sur holds a “Goldilocks” position for many users: