ROBOROCK·FAULT ERR 42 WARN

Roborock Error 42 — Maintenance brush jammed

Severity: Warning — the dock can't scrub the mop-wash tray until the brush is freed S7S8

Last verified: 2026-07-05 Tools: none Time: ~10 min Difficulty: easy

DIRECT ANSWER

Error 42 — spoken as "Error 42. Maintenance brush jammed. Clean it and remove blockages." — hits Ultra docks. The brush that scrubs the mop-washing tray is stuck; where it stops points to the cause.

#meaning · #causes · #fix — link straight to any section

COMMON CAUSES · RANKED

Debris jamming the brush (stops at the left) MOST COMMON

Roborock's rule of thumb — a brush stopped at the left side is physically jammed. Pull out whatever is caught in it.

Dock filter blocked or missing (stops at the right)

Stopped at the right side, the tray's filter is clogged or not seated. Clean it and refit it properly.

HOW TO FIX IT

No battery or electrical work involved in this fix.

Note where the brush stopped

Left side means a jam, right side means a filter problem — this single observation picks your fix.

Clear the maintenance brush

Lift the brush out of the dock's wash tray and remove tangled hair and debris.

Clean and reseat the tray filter

Rinse the filter, then click it back into position.

Run a mop-wash cycle

Trigger a wash from the dock and confirm the brush sweeps the full tray. If it stalls again, contact support.

Did this fix your robot?

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RELATED FIRMWARE

S7 series (S7, S7 MaxV)

SAMPLE DATA — dataset in progress

4.1.2_07984.1.5_11964.3.5_16124.5.3_5936

Firmware timelines are rebuilt monthly from release notes. Versions marked as sample data are community-reported and not yet verified. Full firmware timeline →

Sources

Verification

OFFICIAL SOURCE

Last verified: 2026-07-05 · How we verify a fault code

Corrections

Spotted an error? Report a correction — fixes ship within 48h and are logged on this page.