On Windows, a mouse’s back and forward buttons just work. Plug that same mouse into a Mac and click them in Finder: nothing. No back, no forward, nothing at all.
That’s because Finder doesn’t listen for raw mouse button numbers. It only responds to the ⌘[ (back) and ⌘] (forward) keyboard shortcut. Mice with a proper macOS driver translate their buttons for you. Mice without one — most notably Razer mice like the DeathAdder, Basilisk and Viper, since Razer Synapse is Windows-only, plus plenty of unbranded ones — don’t.
SideNav is a free, open-source menu bar app that fixes it. It listens for those side-button clicks system-wide and turns them into the shortcut, so navigation works exactly the way you’d expect — in Finder, Safari, Chrome, and any other app that understands ⌘[ / ⌘].
Installing
- Grab the latest DMG from Releases and drag SideNav into Applications.
- It isn’t notarized, so the first time, right-click the app and choose Open.
- macOS will add SideNav to System Settings → Privacy & Security → Accessibility in an off state — toggle it on. That’s the permission that lets it see mouse clicks and send keystrokes.
Click the ↔ icon in the menu bar for Enabled (your instant undo — switch it off and your mouse is stock again), Launch at Login, and a one-click Uninstall. Requires macOS 13 Ventura or later.
Will it work with my mouse?
Almost certainly, as long as its side buttons report as HID buttons 3 and 4, which is the near-universal default. If yours don’t, the repo includes a tiny diagnostic script that prints the button number for every click, and the numbers are two constants at the top of main.swift.
How it works
SideNav creates a session-level CGEventTap listening for “other mouse” button events. When it sees button 3 or 4, it swallows the click and synthesizes a ⌘[ or ⌘] key event instead. Everything else passes through untouched. Login-item registration uses Apple’s modern SMAppService API, so it’s always cleanly reversible.
Karabiner-Elements or SensibleSideButtons can do this too, along with a lot more. SideNav is a single-purpose, from-scratch implementation that does exactly one job with nothing to configure. It has no network code at all, and the whole app is about 200 lines — read it. MIT licensed.
Also in the “tiny Mac fixes” department: NaturalOnBattery and WinDot.
Free and open source, and it’s staying that way. If it saved you some time, you can buy me a coffee.