ZacOS 9 redraws the whole Mac OS 9 desktop for Debian Linux, with a SheepShaver for the real classic apps

One developer rebuilt the Platinum look as its own window manager, file browser, menu bar and control panels, with no Apple code inside. Bring your own ROM and classic Mac OS runs in the built-in emulator, and it still talks AppleTalk to a Power Mac.

By Chris Pirillo · October 25, 2026 · 6 min read

Chris at a modern flat monitor showing grey striped-title-bar windows, with a beige vintage computer cabled to it on the desk beside him — Illustration: LockerGnome

Why it matters

The look goes all the way down. Plenty of Linux themes paint Platinum colors over GNOME or KDE. Here, “the window manager, Sniffer file browser, menu bar and every control panel were written for it, so everything looks and behaves alike, down to the scroll arrows,” the project page says. The window manager is its own Wayland compositor, zacos9-wm, written in C on wlroots 0.18, and the rest of the shell is Qt6.

Apple’s parts stay out of it. “No Apple code, ROMs, fonts or icons are included,” and the GitHub README adds sounds to the list. Every asset is original or freely licensed. The busy cursor gives it away, since the spinning watch is gone and an original rainbow dog bone turns while an app starts up.

One person built it for himself. “I built ZacOS for myself, wanting Mac OS 9’s calm, simple desktop on a modern Linux system,” the developer, listed on SourceForge as Adam Lawson, writes. “Once it was good enough to live in, I decided to share it.”

The file browser is called Sniffer, and the README admits it was “formerly Finder.” The Apple menu’s stand-in is the Zac menu, which holds Control Panels, Favorites, Recent items and Automated Tasks. Its Control Panels list runs to 27, from Memory and Appearance to Keychain Access, each with its own small icon in the Platinum palette.

You still run modern software in it. Firefox, LibreOffice, GIMP and the rest of Debian draw in the Platinum look, and a Flathub switch opens up Flatpak apps. The source on GitHub is GPLv3, the same license the SourceForge page lists, so anyone can build it or fork it.

The classic side works with your own files. SheepShaver handles PowerPC Mac OS up to 9.0.4, Basilisk II covers 68k up to 8.1, and a launcher called zacos9-classic picks your ROM by checksum. Sniffer mounts HFS and HFS+ disks and disk images read-only, on purpose, since Linux can’t safely write to every Mac file system. Double-click a StuffIt archive and it extracts with its resource forks kept as hidden AppleDouble files.

Then there’s the network. ZacOS 9 has its own AFP client over AppleTalk, for Macs that only share files that way. The project log says it was “checked live against a Power Mac 7500”: find the server, log in, mount its Macintosh HD on the desktop, copy files both ways. Turn on File Sharing and it works the other way too, with an old Mac’s Chooser finding the ZacOS machine over AppleTalk.

The ISO is about 3.0 GB, and it boots live from a USB stick before you install from the desktop. SourceForge counted 345 downloads in its first week, from October 18 through 24, with Germany and the United States at the top. The project calls itself beta, and the releases come fast: version 1.0.18 landed on October 25.

Steal this

Try it live from the USB stick before you install anything, and pull an extra copy of any Mac disk you plan to plug in. Sniffer mounts them read-only, and old drives fail on their own schedule. Kind of like test-driving a classic car before you sell your daily driver.
Rip your own ROM and system software from Macs you own. ZacOS 9 ships none of them, and the emulator won’t start classic Mac OS without them. This is like a record player: the turntable comes in the box, and the vinyl is yours to bring.
If you’ve got an old Mac on AppleTalk, plug it into the same network and test file sharing both ways first. The AFP client was checked against one Power Mac 7500, and the log says a server going away mid-mount hasn’t been tested. Kind of like a new bridge: one truck made it across, so walk your own load over slowly.

There’s one feature still in the lab. A design doc plans for a classic app’s document windows to sit right beside Linux windows on the same desktop, each one managed by ZacOS like any other window. It’s a feasibility spike so far, working in black and white with one test app, and color is the next proof it needs before classic and modern apps can share one desktop.

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ZacOS 9 redraws the whole Mac OS 9 desktop for Debian Linux, with a SheepShaver for the real classic apps

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