My GE makes a “knocking” sound at the beginning of the cycle. Is that common?

Hi - Thank you for reaching out to us and for having purchased a new GE Appliances dishwasher. It is normal for the dishwasher to make a definitive snap sound when the water valve opens to let the water in to fill the dishwasher. For a repetitive knocking sound, make sure nothing in either rack is interfering with the rotation of the wash arm. If this sound continues and occurs at the beginning of each cycle, you may be experiencing what is called a "water hammer". Water Hammer is a problem caused by the amount of water pressure in your household plumbing. As the dishwasher's water valve closes, the force of water in the pipes can cause the pipes to rattle. This is a plumbing condition and would need a plumber to resolve. If you continue to have an issue or concerns, we recommend calling GE Appliances service at 1-800-432-2737 to schedule an appointment to have your dishwasher checked by an authorized service technician. We hope you find this information helpful. Warm regards - Vikki@GEA