Hello Butch49.

We are sorry to hear about your experience. Grass piles up in rows when mowing due to a few factors, including dull mower blades, mowing too low, and mowing wet grass. A dull blade can tear the grass, leaving larger clippings that accumulate in rows. Mowing too low or when the grass is wet can also cause clippings to clump together. Cross-Cutting, some users intentionally crosscut their lawns by mowing in different directions to create a striped effect. While this can be visually appealing, it can also increase the amount of grass clippings left on the lawn and potentially lead to clumping if not managed properly. If you mow too low, you are removing more than one-third of the grass blade's length, which can lead to clumping. It is recommended to keep the mower deck at around 3.5 inches and mow more frequently to prevent this. As a rule, users should never remove more than one-third of the grass blade's length at a time when mowing. This helps to keep the lawn healthy and reduces the chances of clumping. Wet grass or a dirty mower deck can also cause clippings to stick together and clump more easily, especially if the lawn is damp or you are using a mower with a bagger. Cleaning your mower deck after every use is a good practice, especially if you are mulching or mowing in wet or heavy conditions. While some may clean it a few times a season, more frequent cleaning, like after every mow, helps prevent buildup, maintains optimal performance, and extends the life of your mower. As the lawn becomes consistently maintained you will see the cut and run time improve. Hope these tips help!
If you have exhausted all troubleshooting steps and the problem persists, contact us through Live Chat on www.greenworkstools.com or call Greenworks Pro toll-free helpline 1-855-345-3934. So, our experts can discuss your experience; please have your unit, battery and charger with you along with the model and serial number to complete troubleshooting to ensure quick resolution is provided.