The answer to 'steam cleaner smells bad' is that there are several common causes for a foul odor coming from your steam cleaner. This can be due to built-up dirt, mold, mildew, or bacteria in the machine's water tank, hose, or cleaning head. Symptoms may include a musty, stale, or rotten smell when using the steam cleaner.
To address this issue, you can try some DIY troubleshooting steps like thoroughly cleaning and disinfecting the steam cleaner according to the manufacturer's instructions. This may involve using a cleaning solution, vinegar, or baking soda to remove any buildup. However, if the odor persists or you're unable to fully eliminate it, it's best to call in a professional cleaning technician to inspect and service the machine.