Direct answer
Some cliff sensors interpret very dark patterns as a drop. Cleaning sensors and checking model-specific settings is safer than covering the sensors.
What this covers
- Robot vacuums · cliff sensors
- The exact symptom in the title before component-level repair
- Consumer-accessible controls, connections and maintenance areas
What it does not cover
- ×Smoke, burning odor, swelling, liquid on powered parts or damaged wiring
- ×Opening sealed panels, bypassing interlocks or live-electrical testing
- ×Account ownership, billing or warranty disputes
Observe before changing anything
ReversibleObserve whether the robot stops exactly at dark sections and reports a cliff or drop warning.
Isolate the failing boundary
ReversibleClean sensors and improve lighting, then check whether the manufacturer provides an approved carpet or sensitivity setting.
Apply the narrow correction
ReversibleUse a physical boundary or alternate cleaning method if the surface remains unsupported.
Verify the result and stop at the boundary
ReversibleDo not tape over cliff sensors; that can allow the robot to fall down stairs.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Exact questions
Common follow-ups
What should I check first for “Robot vacuum will not cross a dark rug”?+
Observe whether the robot stops exactly at dark sections and reports a cliff or drop warning.
How do I know whether the problem is external or inside the device?+
Clean sensors and improve lighting, then check whether the manufacturer provides an approved carpet or sensitivity setting.
When should I stop and request repair?+
Do not tape over cliff sensors; that can allow the robot to fall down stairs.
Answer for the exact device and software version shown above.