Menu bar frozen or icons not responding on a Mac? How to restart it
Clicking the clock, Wi-Fi or Control Center does nothing. The two background processes that draw the menu bar, and how to restart each without logging out.
What draws the menu bar?
Two background processes. ControlCenter draws Control Center, the clock and most of Apple's icons; SystemUIServer handles some of the others. Each restarts by itself if it stops, so restarting them is safe.
How do I restart the menu bar?
Open Terminal and run:
killall ControlCenter; killall SystemUIServerThe icons blink and come back within a few seconds. Without Terminal, open Activity Monitor, search for each name, and quit it with the stop button.
What if the app menus on the left are frozen?
The left side belongs to the front app. If its menus do not open, that app is stuck: press ⌥ ⌘ Esc and force quit it. See force quit.
What if a third party icon is frozen?
Each app's own menu bar icon belongs to that app. Quit and reopen the app. If it has no window, find it in Activity Monitor.
What if it keeps happening?
- Remove menu bar apps you do not need, one at a time, to find the one causing it.
- Install macOS updates; menu bar bugs are often fixed in point releases.
- Restart the Mac, which clears every process at once.
The rest of the system: relaunch Finder, a frozen Dock, and what WindowServer is.
Checked on 22 October 2026 on a MacBook Air (M1) running macOS 27.0.1: ControlCenter and SystemUIServer are both running processes on this Mac.
Questions
How do I restart the menu bar on a Mac?
Run killall ControlCenter and killall SystemUIServer in Terminal. Both restart at once.
Why is Control Center not opening on my Mac?
The ControlCenter process may be stuck. Restart it with killall ControlCenter.
Is it safe to kill SystemUIServer?
Yes. It restarts by itself straight away.
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