Relente

Relente is a native Mac app that creates a bootable USB drive from a macOS installer, so you can do a clean install of macOS. It wraps Apple's own createinstallmedia tool in a guided, visual flow: pick an installer, pick a USB drive, review, and create.

It is written in Swift and SwiftUI, and only works with macOS installers and removable drives (USB drives and SD cards). Internal disks and external SSDs or hard drives are never offered as a destination.

Warning

Relente is in early development and is not usable yet. When it is, it will erase the drive you choose. Always double-check the drive before confirming.

Get started

Requirements

• A Mac running macOS 14 Sonoma or later, with Apple silicon or an Intel processor. Older Macs matter here, so the oldest supported version is only dropped when keeping it becomes costly; this is reviewed once a year.
• A macOS installer from Big Sur (11) onwards, in any of these forms:
  • Install macOS <name>.app
  • A .dmg that contains the installer app
  • InstallAssistant.pkg
• A USB drive or SD card of at least 16 GB. Everything on it will be erased.

Install

There are no releases yet. Signed and notarized builds will be published on the Releases page.

To build it yourself, see BUILDING.md.

Create a bootable USB drive

1. Open Relente and approve its system helper when macOS asks. For live USB creation, enable Relente in System Settings → Privacy & Security → Full Disk Access and allow its helper under General → Login Items. You can browse installers and choose a USB before enabling Full Disk Access; Relente checks write access before starting an erase.
2. Installer: choose one of the macOS installers found on your Mac. Downloading installers from Apple is planned for a later step.
3. USB drive: choose the drive to use. Drives that are too small are marked.
4. Review: check what will be erased, confirm, and authorize the erase with Touch ID when available or your administrator password otherwise.
5. Creating: Relente asks its helper to run Apple's signed createinstallmedia, shows available progress and elapsed time, and verifies the resulting installer volume before marking it ready. Activity offers a compact history and technical output. The command erases the selected drive.

When it's done, the app explains how to start up from the drive on a Mac with Apple silicon or with an Intel processor. Apple's guide Create a bootable installer for macOS covers the same steps from the command line.

Uninstall

1. In Relente, choose Uninstall System Helper… from the app menu. (You can also turn it off in System Settings → General → Login Items & Extensions.)
2. Move Relente to the Trash.

How it works

Relente has two parts:

• The app runs without special privileges. It shows the interface, finds macOS installers, and detects removable drives.
• A small system helper runs as root, registered through SMAppService. It formats a drive and runs the selected installer's signed createinstallmedia with real progress. It has no network access and accepts requests only from the signed Relente app.

Before erasing anything, the helper checks on its own that the drive is external and removable, that it is not the startup disk, and that it's the same physical drive you confirmed. It also validates Apple's signature on the installer and its createinstallmedia tool. See SECURITY.md for details.

Contributing

This is a personal project and pull requests aren't accepted for now. Bug reports and ideas are welcome as issues. See CONTRIBUTING.md.

Project status

Early development. The roadmap (specs refer to these as "roadmap step N"):

1. Project setup
2. Folder structure and design system
3. Static screens with sample data: 001 Installer ✓, 002 USB drive ✓, 003 Review ✓, 004 Creating (+ Error) ✓, 005 Done ✓
4. Assistant navigation and animations: 006 Assistant navigation ✓
5. Real disk and installer detection: 007 Real detection ✓
6. System helper, XPC and security checks (includes the Permissions screen)
7. createinstallmedia with live progress
8. Signing, notarization, Authorization Services compatibility across supported Macs, and first release
9. Download installers from Apple (Download screen)

Relente is built with spec-driven development: every feature has a specification in specs/, and the project's rules are in AGENTS.md.

License

Relente is released under the MIT License.

Relente is not affiliated with or endorsed by Apple. macOS is a trademark of Apple Inc.