my s9+ is missing huge spots in the middle of the room, it just goes around them in a weird square pattern.

Diagnosis

The "square pattern" behavior in the iRobot Roomba s9+ is a classic symptom of a failure in the vSLAM (Visual Simultaneous Localization and Mapping) system. Unlike older models that rely solely on bump sensors, the s9+ uses an upward-facing camera to identify ceiling features and landmarks to orient itself. When the robot cannot "see" a consistent anchor point on the ceiling, it loses its position in the virtual map. To compensate, it enters a recovery mode where it moves in rigid, geometric patterns to try and find a known landmark, effectively skipping the center of the room because it believes it is navigating an obstacle or a boundary it cannot resolve. This usually happens due to "visual noise" or sensor occlusion. If the camera lens is smudged with a thin film of dust or if the room has high-contrast glare from a skylight or very dim lighting, the image processing chip cannot lock onto the ceiling. You can confirm this by checking the iRobot Home App; if the "Cleaning Map" shows the robot skipping a large area despite the robot physically moving around the perimeter of that gap, the internal coordinate system has drifted, and the robot is essentially "blind" to the center of the room.

How to Fix It

To restore precise navigation and eliminate the skipping behavior, follow these exact steps to recalibrate the visual sensors:

1. Power down the s9+ completely by pressing and holding the CLEAN button for 10 seconds until the light ring fades.
2. Locate the vSLAM camera—the circular glass lens on the top of the chassis. Use a dry, high-density microfiber cloth to wipe the lens in a circular motion. Avoid using window cleaners or alcohol, as these can strip the anti-reflective coating on the lens.
3. Clean the infrared (IR) sensor window located immediately adjacent to the camera. Use a can of compressed air to blow out any microscopic debris trapped in the seam between the sensor and the plastic casing.
4. Check your lighting. The s9+ requires a minimum of 40 lux to map accurately. If you are cleaning in a room with blackout curtains or dim mood lighting, turn on all overhead lights or open the blinds.
5. Perform a "Hard Reset" of the map: Open the iRobot Home App, go to Map > [Select Your Map] > Delete Map. This forces the robot to rebuild its spatial coordinates from scratch rather than relying on a corrupted map file.
6. Place the robot on the Clean Base and start a new "Clean All" cycle. Ensure the robot starts from the base so it has a fixed "Home" coordinate to reference.

If That Didn't Work

• Check for "Invisible Boundaries." If you have set up Virtual Wall Barriers or "Keep Out Zones" in the app, a slight misalignment in the map can cause the robot to treat the center of the room as a forbidden zone. Delete all Keep Out Zones and run a test clean to see if the skipping persists.
• Inspect for high-contrast floor patterns. If you have a very dark, high-contrast rug or a black-and-white checkered floor in the center of the room, the cliff sensors (located on the underside) may be misinterpreting the dark colors as "cliffs" or drops. To test this, temporarily cover the center of the rug with a light-colored towel; if the robot now cleans the area, the issue is sensor-based, not navigation-based.
• Update the Firmware. Ensure your s9+ is running the latest version. Navigate to Product Settings > Software Update. A known bug in older firmware versions caused "mapping drift" where the robot would incorrectly calculate its distance from the Clean Base.
• Check for mirror interference. If you have floor-length mirrors or highly reflective metallic furniture in the room, the vSLAM camera may be seeing a "ghost" reflection of the ceiling, confusing its position. Try covering the mirror with a sheet to see if the robot resumes a normal path.

Heads Up

• Avoid placing the Clean Base in a cramped corner. The s9+ needs a clear 1.5-foot radius in front of the base to properly orient its camera before starting a mission.
• Clean the cliff sensors on the bottom of the unit every 30 days with a dry cotton swab to prevent "false cliff" readings that cause the robot to avoid certain areas of the floor.
• If you rearrange your furniture significantly (moving a couch or table), always delete the current map and let the robot re-map the room to prevent it from trying to navigate around objects that are no longer there.
• Ensure the Clean Base is plugged into a wall outlet directly, rather than a surge protector or extension cord, as voltage drops can occasionally cause the robot to lose its "Home" coordinate during docking.