Why does my litter box say the drawer is full when it isn’t?

The sensor is usually reading residue rather than volume: waste stuck to the drawer wall, a mis-seated liner, or dust on the optical window all report a full drawer.

False full-drawer alerts are a cleaning problem in almost every case.

Residue on the wall

Waste that has stuck where the sensor looks reads as a full drawer whatever is underneath. Wash the drawer, dry it, and the alert usually clears.

A liner out of place

A liner that has slipped across the sensor window does the same thing. Reseat it so it sits flat against the walls.

Dust on the window

Same cause as a stalled cycle: fine litter dust on an optical sensor. Wipe it when you change litter.

If it persists

Reset the counter if your machine has one — some count cycles rather than measuring volume, and a reset is part of normal emptying. Then, if it still misreports on a clean drawer, that is a support conversation with the error code from the app.

This does not replace your device’s manual. Blade temperatures, locking mechanisms and cleaning procedures differ from model to model, and the manufacturer’s instructions take precedence over anything written here. Unplug a device before dismantling it, check a hot blade or an air nozzle against your own hand before it goes anywhere near an animal, and keep a mechanism that closes or rotates under supervision until you know how it behaves.