Machine is very noisy during grinding; loud rattling or screeching sounds are heard.

Safety first: Turn off and unplug the machine before working near the grinder.

Step-by-step checks:

• Empty hopper: Remove all beans from the hopper. Vacuum out loose beans and grounds.
• Check for foreign objects: Inspect the hopper and visible grinder inlet for stones or hard objects.
• Test with small amount of beans: Add a small quantity of beans and run a single coffee. If noise persists, stop using the grinder to avoid further damage.

When to call a technician: Persistent loud or metallic noises indicate internal grinder damage. The grinder assembly should be inspected and likely replaced by a professional.