🌐 Website: protonos.org | ⬇️ Download: SourceForge
A secure, Windows-familiar Linux distribution built for small business operations, zero learning curve, instant productivity, no telemetry, secure and stable out of the box.
The zero-friction, high-performance Linux distribution designed for small businesses transitioning from Windows.
Proton OS is a lightweight, secure, and intuitive operating system built on top of Debian 13 (Trixie). Designed specifically for small office environments, non-technical teams, modern and legacy hardware. Proton OS delivers a familiar desktop experience with zero learning curve and zero downtime.
Current release: Proton OS 1.0 Core
- Collabora Office replaces LibreOffice and ONLYOFFICE — opens .docx, .xlsx, .pptx and .odt files.
- Winboat 0.9.2 now runs on Podman instead of Docker.
- earlyoom is on by default and stops a runaway app before the desktop freezes.
- Installer: Proton-branded boot menu, 8+ character passwords required, optional "Third-party software" step for Microsoft fonts, and a clean automatic restart after installation.
- Look: Win11-style icons, Win10OS cursors and new Proton wallpapers (Business Slate by default, plus Magenta and Paper) on the desktop, lock screen, login screen and USB boot menu.
- Branding: About This System shows Proton OS 1.0 with the Proton logo.
- Leaner image: leftover GNOME services, developer tools and unused packages removed. Variety, Docker, LibreOffice and ONLYOFFICE are gone.
More screenshots on SourceForge.
- Familiar Desktop Interface: Intuitive layout, Start-style application launcher, and system panel designed to mirror traditional Windows workflows.
- Instant Productivity: Pre-configured out of the box with web-app integration for Microsoft 365 and Teams.
- Debian 13 Stability: Rock-solid upstream core with low system overhead and zero forced bloatware or forced snap packages.
- Built-in Security: Security controls enable by default, automated background security patch update, and built-in firewall configurations.
- Hardware Friendly: Extends the lifecycle of existing office PCs, significantly lowering hardware refresh costs.
- Windows App Compatibility: Run real Windows applications seamlessly alongside native Linux apps via Winboat's Podman + KVM integration, no dual-boot or full VM required.
- Familiar Shortcuts: Ctrl+Shift+Esc opens System Monitor (like Task Manager) and NumLock is on at login.
- Secure Boot: Boots on UEFI with Secure Boot enabled, using the Microsoft-signed shim.
Proton OS ships ready to use out of the box:
- Brave Browser — privacy-focused browser, installed via Brave's official repo
- Firefox ESR — kept for the web apps
- Collabora Office — full office suite (documents, spreadsheets, presentations) with Microsoft Office format compatibility, installed from Flathub
- Winboat 0.9.2 — run Windows applications directly on Proton OS via Podman + KVM virtualization
- earlyoom — memory safety switch, enabled by default
- Microsoft core fonts — optional, selected in the installer and installed on first boot when online
See software/ for exact install commands and Winboat's prerequisites.
| Proton OS | Windows 10/11 | Stock Debian/Ubuntu | |
|---|---|---|---|
| License cost | Free | Paid per device | Free |
| Telemetry | None by default | Built-in, opt-out varies | None by default |
| Familiar desktop for Windows users | Yes, Start-style launcher, taskbar layout | N/A | No, requires learning a new workflow |
| Firewall enabled by default | Yes (UFW, deny incoming) | Yes | Varies by distro/install |
| AppArmor / mandatory access control | Enabled by default | N/A (different security model) | Often not enabled by default |
| Automatic security updates | Yes, out of the box | Yes | Manual setup typically required |
| Office suite included | Yes (Collabora Office) | No (separate purchase/subscription) | Varies |
| Run Windows-only apps | Yes, via Winboat (Podman + KVM) | N/A | Requires manual Wine/VM setup |
| Hardware support for older PCs | Yes, extends lifecycle of existing hardware | Increasing minimum requirements each version | Yes, generally lightweight |
| Forced OS updates/reboots | No | Yes | No |
Will my existing Windows applications work?
Native Linux equivalents are pre-installed for common tasks (office, browsing, PDFs). For Windows-only software without a Linux version, Winboat runs it directly via a lightweight Podman + KVM Windows environment — see software/winboat-prerequisites.txt for setup details. When Winboat's setup asks for a container runtime, choose Podman.
Will my Word and Excel files open? Yes, in Collabora Office. Tick the optional Microsoft fonts in the installer so documents look the same as on Windows.
What about my printer, scanner, or other peripherals? Proton OS is built on Debian 13, which has broad hardware support out of the box. Most USB printers/scanners work via standard Linux drivers (CUPS). Check manufacturer Linux driver availability for specialized hardware.
Can our IT team manage this remotely like a Windows fleet? Standard Linux remote administration tools apply (SSH, VNC, etc.). You can use standard RMM that are on the market that support linux.
Is this actually secure, or just "secure by default" marketing?
Every security claim in this repo is backed by verified configuration, documented under security/ — including exact package versions and command output used to confirm each setting (firewall, AppArmor, automatic updates). Nothing here is assumed; it was checked against a live install.
What if something breaks? Open an issue on this repository. Known hardware quirks and their fixes are tracked as we find them (see Repository Structure below for where fixes are documented).
Is my hardware supported? Proton OS runs on most UEFI-based hardware and modern-to-slightly-older machines. One known compatibility quirk (older BIOS/xHCI USB controllers) is documented; broader legacy BIOS testing is ongoing.
Confirm your downloaded ISO hasn't been corrupted or tampered with:
Latest release: ProtonOS-Core-1.0-64bit-2026.10.01.iso (Updated 2026-10-02)
| Algorithm | Checksum |
|---|---|
| SHA-256 | b767091478db7eb5be28718efffb54e827e2ae6eff3c5fd7a349c1ea4c0684b3 |
Linux/macOS:
sha256sum ProtonOS-Core-1.0-64bit-2026.10.01.isoWindows (PowerShell):
Get-FileHash ProtonOS-Core-1.0-64bit-2026.10.01.iso -Algorithm SHA256Compare the output against the SHA-256 value above — they should match exactly.
GPG-signed releases are planned for a future update to provide stronger authenticity verification beyond checksums.
Proton-OS/
├── branding/ # About page, os-release, icon defaults, wallpaper exclusion, look-and-feel notes
├── calamares/ # Installer: password rule, EFI id, restart script, third-party fonts page
├── grub/ # Live USB boot menus (grub.cfg, isolinux.cfg) and the Proton GRUB theme
├── plymouth/ # Boot splash config - plymouthd.conf
├── sddm/ # Login screen: login.defs, kde_settings.conf, Slate background
├── skel/ # Default user settings (/etc/skel overlay)
├── packages/ # Package holds and every apt/flatpak install and removal
├── software/ # Pre-installed apps (Brave, Collabora, Winboat/Podman, earlyoom)
├── security/ # Verified security defaults (AppArmor, UFW, unattended-upgrades)
├── BUILD.md # From-scratch Cubic build guide
├── HARDWARE.md # Tested hardware and known boot quirks
├── CONTRIBUTING.md # How to report bugs and help
├── LICENSE # GNU General Public License v3.0
└── README.md # Repository overview