Build macOS Installer image via Github Action – No Mac Required

• Support macOS 10.7 Lion through macOS 26 Tahoe installers.
• Download macOS installers exclusively from official Apple sources.
• Includes intelligent file size optimization to produce the smallest possible installer images.

Supported formats:

• ISO – True DVD/CD format compatible with Proxmox VE, QEMU, VirtualBox, and VMware
• DMG – For create bootable macOS installer USB drives on Windows with Rufus or on Linux with dd

Available workflows:

• Recovery ISO (Recommended) – Lightweight recovery image (build takes ~2-5 min) • Best for virtualization
• Full Installer – Complete offline installer (build takes ~10-60 min, 5-18GB) • Best for offline use

Important

• Use the "Build macOS Recovery ISO image" workflow unless you really need an offline installer.
• GitHub-hosted runners are a free public resource — please use them responsibly.
• If you already have macOS VM, you can build macOS ISO/DMG image using the following command (replace tahoe with your desired version):

curl -s https://raw.githubusercontent.com/LongQT-sea/macos-iso-builder/main/mkmaciso | bash -s tahoe

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Usage

Tip

Click here to watch a GIF showing how to complete steps 1–7

1. Fork this repository (requires a GitHub account).

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

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

4. Select the "Build macOS Installer ISO/DMG image" or "Build macOS Recovery ISO image" workflow from the left sidebar.

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.

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

8. Wait for the workflow to complete (this may take 10–60 minutes).

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

10. Download the artifact (e.g., macOS_Sequoia_15.7.3.iso).

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

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Tip

After flashing the DMG image to the USB drive with Rufus, there will be free/unallocated space remaining on the USB drive. Use Disk Management to create a new FAT32 partition and place your EFI folder there if needed.

Note

By default, artifacts are kept for 7 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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Legal Notice

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