killall on Mac: Restart Finder, Dock, and More

killall quits every process with a given name. That sounds destructive, but for macOS system components it's the opposite: Finder, the Dock, and the menu bar respawn automatically within a second or two, picking up any settings changes as they do. It's the reason almost every hidden-settings tweak ends with a killall line instead of "now reboot your Mac."

Why killall is safe for system processes

System components like Finder and the Dock are managed by launchd, macOS's process supervisor. When one quits — for any reason — launchd relaunches it immediately. So killall Dock doesn't leave you Dock-less; it gives you a fresh Dock that has re-read its preferences. Your windows, apps, and files are untouched. The only thing you lose is transient state, like which Dock stack was open.

Regular apps are different: killall Safari just quits Safari without asking about unsaved state, and nothing relaunches it. Use killall on apps only when they're unresponsive — and prefer Force Quit (⌘⌥Esc) first, since it's harder to typo.

The killall commands worth knowing

• killall Finder — restarts Finder. Applies Finder tweaks (hidden files, path bar defaults), fixes a frozen desktop or unresponsive Finder windows. Note: it also cancels any file copies Finder has in flight, so let transfers finish first.
• killall Dock — restarts the Dock, which also owns Mission Control, Spaces, Launchpad, and Stage Manager. Applies every Dock tweak and un-sticks a Dock that stopped responding to hovers.
• killall SystemUIServer — restarts the process behind parts of the menu bar. Useful on all supported versions when menu-bar extras misbehave, though on Ventura and later many status items have moved to Control Center.
• killall ControlCenter — restarts Control Center, which on macOS 13–15 owns the clock, Wi-Fi, Bluetooth, battery, and most other right-side menu-bar icons. This is the one to reach for when those icons freeze or disappear.
• killall cfprefsd — restarts the preferences daemon. Occasionally needed when a defaults change refuses to stick; it respawns instantly.
• killall NotificationCenter — restarts Notification Center when banners or widgets get stuck.

# the classic pair after a settings tweak
killall Finder
killall Dock

There's no undo command for a restart — the process comes back on its own. If you restarted something to apply a tweak you now regret, undo the tweak itself (usually with defaults delete) and run the same killall again.

Gotchas: case, "No matching processes", and the one to avoid

Three things trip people up:

• Names are case-sensitive. killall dock fails; it's killall Dock. Match the name shown in Activity Monitor exactly.
• "No matching processes belonging to you were found" means either the name is wrong, the process isn't running, or it belongs to another user or root. For root-owned daemons you need sudo — for example sudo killall -HUP mDNSResponder when flushing DNS. Don't reach for sudo reflexively; user processes never need it.
• Never kill WindowServer. killall WindowServer (or killing loginwindow) instantly ends your session and dumps you at the login screen, closing everything unsaved. It technically "works," which is exactly the problem.

Where killall fits in your tweak workflow

Most of the time you'll run killall right after a defaults write command, since preferences are only read at launch. If you're new to that side of things, start with our guide to changing hidden settings with defaults write — every example there comes with its matching killall and its undo.