Explainer
Mac trackpad palm rejection explained
Palm rejection tries to separate intentional finger gestures from incidental contact. It is useful, but no filter can know your intent perfectly, especially around the moment you stop typing.
What palm rejection is trying to decide
A large trackpad can receive several contacts at once: the finger you intend to use, the edge of a thumb, or part of a palm resting near the keyboard. macOS interprets the contact pattern, movement, pressure, and timing to decide which input should count.
The decision is probabilistic. If the system rejects too much, deliberate gestures feel broken. If it rejects too little, an accidental tap can move the insertion point, select text, start a drag, or trigger a button.
Why accidental clicks can survive the filter
The difficult moment is often the transition between typing and pointing. A contact immediately after the last key press can look like the start of an intentional gesture. Tap to click also turns a light contact into a click, while physical click pressure adds a clearer signal of intent.
That is why turning off Tap to click or selecting a firmer Click setting can help. Apple documents both controls in current Trackpad settings.
A timed guard uses a simpler rule
PalmGuardian does not try to classify the shape of your hand. It uses a time boundary: after a key press, pointer input pauses for the delay you choose. When the window ends, input returns normally.
When PalmGuardian is a reasonable fit
- The insertion point moves because your palm or thumb touches the trackpad while you type.
- You want to keep Tap to click enabled.
- You prefer a short automatic delay over disabling the trackpad completely.
- You can tolerate a brief pause before pointing immediately after a keystroke.
When to investigate something else
- The pointer moves while your hands are away from the Mac.
- The problem occurs in only one app or document.
- The trackpad clicks, drags, or selects continuously.
- Liquid, impact, swelling, or a recent repair may be involved.
In those cases, disconnect other input devices, restart, compare apps, and seek hardware support if the behavior persists. A typing guard should not conceal a safety or repair issue.
A predictable time boundary
Set the guard from 0.1 to 2.0 seconds.
Native, signed, notarized, and private by design.