my q7 max is vacuuming but leaving obvious lines of debris behind, especially on hard floors.

Diagnosis

The "streaking" effect on hard floors with the Roborock Q7 Max is almost always caused by a localized drop in static pressure within the vacuum path. While the motor may sound like it is running at full power, a partial obstruction—often a "debris plug" consisting of compressed pet hair, cardboard shards, or clumps of dust—has formed in the narrow throat between the main roller brush and the dustbin intake. This restricts the CFM (cubic feet per minute) of airflow, meaning the vacuum can lift light dust but lacks the suction velocity to pull heavier debris from the floor into the bin. You can confirm this by performing a "suction test." Place a single piece of lightweight tissue paper over the main brush intake while the unit is running. If the paper is not sucked tight against the intake or flutters inconsistently, you have a blockage. Additionally, check the main roller brush for "hair rings"—tightly wound bands of hair around the ends of the brush—which prevent the bristles from effectively flicking debris into the suction channel, leaving those tell-tale lines of dirt behind.

How to Fix It

To restore full suction and eliminate debris lines, follow this deep-cleaning sequence:

1. Power down the unit and remove the dustbin entirely to expose the internal suction throat.
2. Flip the robot over and press the two release tabs on the main brush cover. Lift the cover and pull the main roller brush out of the chassis.
3. Inspect the ends of the roller brush. Use a pair of scissors or a seam ripper to cut through the hair wraps on the bearing caps at both ends of the brush. If the brush cannot spin freely, the debris will not be channeled correctly.
4. Locate the circular suction intake hole (the throat) inside the robot's belly, where the brush usually sits. This is the primary bottleneck.
5. Using a long, thin, blunt object—such as a plastic chopstick or a flexible pipe cleaner—gently probe the interior of the suction channel. Push any compacted debris forward toward the dustbin opening.
6. Remove the HEPA filter from the dustbin and tap it firmly against a hard surface. Use a vacuum cleaner with a hose attachment to suck out any dust trapped inside the filter pleats.
7. Reinstall the brush, snap the cover back into place, and slide the dustbin in firmly, ensuring the seal is airtight.

If That Didn't Work

• Check the Side-Brush Tension: Inspect the three-arm side brush. If the bristles are splayed outward or the brush is clogged with hair at the axle, it will fail to sweep debris into the path of the main brush, leaving lines of dirt along the edges of the room. Trim splayed bristles with scissors or replace the brush if it no longer maintains a slight inward curve.
• Inspect the Dustbin Gasket: Examine the rubber seal around the rim of the dustbin. If there is a tear or if a piece of debris is trapped in the seal, the robot will lose vacuum pressure (a "leak"), significantly reducing the suction power at the floor level. Wipe the seal with a damp cloth to ensure a vacuum-tight fit.
• Verify Suction Mode Settings: Open the Roborock app and ensure the device is not accidentally set to "Quiet" or "Balanced" mode. For hard floors with heavy debris, switch the setting to "Max" or "Turbo." If the lines persist only in "Quiet" mode, the motor is simply not providing enough lift for the specific type of debris in your home.
• Clean the Sensor Array: Use a dry microfiber cloth to wipe the cliff sensors and the wall sensor. If the robot thinks it is encountering an obstacle or a "drop," it may momentarily fluctuate the motor speed or change its pathing, which can result in missed strips of flooring.

Heads Up

• Filter Warning: Never wash the HEPA filter with water unless you allow it to air-dry for a full 24 hours. A damp filter creates a massive air restriction that can lead to motor overheating and permanent suction loss.
• Brush Maintenance: Clean the main roller brush and the end-cap bearings once every two weeks. Accumulated hair on the bearings increases friction and slows the brush's RPM, directly contributing to streaks on the floor.
• Bin Capacity: Do not let the dustbin fill past the "Max" line. Once the bin is overfilled, the airflow path is physically blocked, which causes the robot to leave debris behind even if the suction channel is clear.