Diagnosis
The dustbin full sensor is obstructed or faulty. This is often caused by fine dust coating the infrared sensor window inside the bin compartment.
How to Fix It
Remove the dustbin. Look inside the robot's bin cavity for a small, clear plastic sensor window. Use a dry microfiber cloth to wipe this window completely clean. Also, wipe the corresponding sensor area on the dustbin itself. Reinsert the bin firmly until it clicks.
If That Didn't Work
The filter may be incorrectly seated or clogged. Remove the filter from the dustbin, tap it clean, and ensure it is snapped fully back into its correct position before reinserting the bin.
Heads Up
Do not wash the filter before every use. A damp filter will cause false 'full' readings. Only wash it monthly and let it dry for 24 hours.