A musty smell from a mop cloth can be related to moisture, but odor alone does not prove that mold is present or identify a failed part. Note the robot and dock model, when the pad was last washed, whether it dried between runs, and whether the odor comes from the cloth, tank, or dock.
Check the pad and drying routine
Remove the mop cloth only if the model’s instructions allow it. Clean it and let it dry using the washing and drying method in the exact owner’s guide. If the robot will be unused for a while, the manufacturer may require the pad to be removed rather than left damp on the robot or in the dock. Do not use bleach, fragrance, detergent, or another cleaning solution unless the exact manufacturer approves it for that pad and water system.
Dreame’s North American support guidance lists a humid home or a mop cloth that did not dry properly before extended storage as possible odor causes. It recommends removing the cloth and drying it in a cool, well-ventilated place during a long period of non-use. The same page recommends a named Dreame/Chasing cleaning solution; that advice is manufacturer-specific. The article does not identify every compatible model or establish that the solution is approved in every region, so check the current manual and local support page before using it.
Check a named tank or dock
For the eufy X10 Pro Omni (T2351), the manual recommends cleaning the dirty-water tank after mopping to help prevent mildew and unpleasant smells. Before maintenance, power off the robot and unplug the power adapter; remove the tank, empty it, and rinse it under running water. These steps are for the named model; use its manual for any other tank care.
For the Roborock Qrevo Edge Series robot RRE0VCM with dock EWFD30HRR, check the app’s drying settings if the mop still smells after a wash. The manual says auto-drying can be disabled, drying ends early if the robot leaves the dock, and a humid environment may call for a longer duration set in the app. Avoid touching the drying air outlets during or just after drying because they can be hot. The manual does not establish a regional retail or app-version crosswalk, so confirm that the exact robot and dock match before applying these checks.
If the odor returns
If a pad remains wet after the normal wash or drying cycle, check the robot’s water, pad-washing, and drying instructions for the exact model. A leak, pooled water, or a dock error needs its own diagnosis; do not open a pump or dock to remove the smell. If the odor is accompanied by heat, smoke, liquid near electrical parts, or visible damage, stop using the robot and contact the manufacturer.
There is no universal mop-pad cleaning chemical or drying schedule. Match the care method to the robot, dock, pad type, and country. If water is not reaching or washing the pad, see dry mop and no-water diagnosis.