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Force-Close a Frozen Window with xkill

Run xkill and click any misbehaving window to terminate that application immediately.

Linuxdesktopxkillprocessx11Low risk
Run `xkill`, then click the frozen window to force it to close.

01Command

Command
$ xkill

02What it does

xkill turns the cursor into a skull/cross and closes the selected window's X connection, which ends the app without asking it to clean up — the graphical equivalent of kill -9 for one window. Press Escape or right-click to cancel without killing anything. On Wayland sessions xkill cannot target native Wayland windows; use GNOME's 'Force Quit' dialog or `killall <process>` instead.

03Risk

RiskLow risk
Requirementsx11-apps/xorg-xkill package on an X11 session (bundled on most desktop installs). Alternative: `killall appname` once you know the process name.
!Warning: Force-killing loses unsaved work in that window — try the app's own close button or `kill -TERM` on the process first.

04Undo

✓No undo needed — this command does not change persistent state.

05Sources

  • xkill(1) - Linux manual page
    Ubuntu Manpages · technical · 2026-09-17
    Evidence: xkill forces the X server to close the connection of the application whose window you click, forcing it to exit.

Last verified: 2026-09-18 · Category: System & Settings