macOS Installer ISO Builder with GitHub Actions

Generate bootable macOS installer ISO or DMG images directly from Apple servers via GitHub Actions. Includes intelligent file size optimization to achieve absolute smallest possible installer images.

Supported formats:

• ISO – True DVD format compatible with Proxmox VE, QEMU, VirtualBox, and VMware
• DMG – For creating bootable macOS installer USB drive on Windows/Linux with dd, BalenaEtcher, Rufus

Workflows available:

• macOS Recovery ISO (Recommended) – Lightweight recovery image (build takes ~2-10 min) • Best for virtualization
• macOS Full Installer – Complete offline installer (build takes ~20-60 min, 5-16GB) • Best for offline use

Note

Due to GitHub Actions usage limits, use the Build macOS Recovery ISO workflow unless you specifically need an offline installer.

Already have a macOS virtual machine? Create full installer ISOs locally on your VM using Create_macOS_ISO.command.

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Usage

1. Fork this repository.

2. Go to the Actions tab in your forked repository.

3. Click the green button "I understand my workflows, go ahead and enable them".

4. Select the "Build macOS Installer ISO/DMG image" workflow.

5. Click the "Run workflow" button.

6. Configure the workflow inputs:

   • macOS version – Choose a version (Sequoia, Sonoma, etc.).
   • Image format – Choose iso for virtual machines or dmg for bootable USB drives.
   • Specific version (optional) – Enter a version like 15.6.1, or leave blank for the latest.

7. Click the green button "Run workflow" to start the build.

8. Wait for the workflow to complete (this may take 15-60 minutes).

9. Open the completed workflow run and scroll to the Artifacts section.

10. Download the artifact (e.g., macOS-Sequoia-15.6.1-ISO).

Tip

Enable Cloudflare WARP for faster downloads.

11. Extract the ZIP file to get your .iso or .dmg file.

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Note

By default, artifacts are kept for 3 days. You can change this in the workflow YAML file.

Tip

• For best performance, use a macOS VM on Proxmox VE with iGPU or dGPU passthrough.
• Install macOS on Proxmox VE using LongQT-sea/OpenCore-ISO.
• For Intel GVT-d iGPU passthrough, see LongQT-sea/intel-igpu-passthru.

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Known Issues

You may occasionally encounter hdiutil: couldn't eject "disk4" - Resource busy. If this occurs, simply re-run the workflow.

Legal Notice

This tool downloads macOS images directly from Apple's servers. Users are responsible for complying with Apple's Software License Agreement.