Why is my Mac's pointer jittering or jumping?
A pointer that won't sit still looks the same on screen whatever the cause. Sometimes the mouse or trackpad is at fault. Sometimes nothing is broken and the pointer is copying a small shake in the hand that holds it. The fixes are different, so find out which one it is first.
The short answer: take your hand off the mouse or trackpad and watch the pointer for ten seconds. If it still moves, the device is the cause: clean the sensor, try another surface, charge the mouse and move its receiver or the charger. If it only shakes while you hold the mouse, the pointer is most likely copying your hand: lower the tracking speed and turn off pointer acceleration, and if that isn't enough, use a tremor filter.
How do I tell whether it's the mouse or my hand?
Put the mouse down and let go of it completely, or lift every finger off the trackpad. Watch the pointer for ten seconds. If it drifts, twitches or jumps with nothing touching the device, the device or its connection is at fault. If it stays still and only shakes when you hold the mouse, the shake most likely comes from the hand: the pointer follows small movements of the hand too, and a fast pointer makes them easy to see. A dirty sensor or a shiny surface can still make the pointer skip while you move it, so if it jumps rather than shakes, try the fixes below as well. A shake that is new or getting worse is worth mentioning to a doctor.
What fixes a pointer that moves by itself?
- Check the surface. Glass, glossy wood and busy patterns confuse an optical sensor. Try a plain mouse pad or a sheet of paper.
- Clean the sensor. Turn the mouse over and remove dust or hair from the lens. On a trackpad, dry your fingers and wipe the surface.
- Charge it. A wireless mouse or trackpad with a low battery can skip and stutter. Charge it fully and see whether the jitter stops.
- Move the receiver. A mouse with a small USB receiver works best with the receiver close to it. USB 3 ports, hubs and drives right next to the receiver can interfere with it: plug it into another port, or into a short extension cable.
- Try another charger. If a MacBook's trackpad jitters only while it's charging, try another power adapter or another wall socket.
- Swap to find the fault. Try the mouse on another computer, or another mouse on this Mac. If the jitter follows the mouse, the mouse is at fault.
What helps when the pointer only shakes in my hand?
- Lower the tracking speed. System Settings › Mouse › Tracking speed, or System Settings › Trackpad › Point & Click › Tracking speed. The same shake then moves the pointer less.
- Turn off pointer acceleration. System Settings › Mouse › Advanced… › Pointer acceleration. A quick shake then doesn't throw the pointer further than a slow movement would.
- Rest the arm. A forearm resting on the desk shakes less than a hand held in the air, and a light grip shakes less than a tight one.
- Stop the pointer growing. If the pointer keeps getting bigger by itself, turn off System Settings › Accessibility › Display › Shake mouse pointer to locate.
These calm the shake by making all movement smaller. How to steady a shaky pointer explains what else you can do.
Can a tremor filter fix a jittering mouse?
Not when the mouse is at fault. A tremor filter works on the movement the Mac receives from your hand: it can't repair a dirty sensor, a weak battery or a receiver that loses its signal. Fix the hardware first. A filter is for the second case, a pointer that shakes because the hand does.