Hello Colorado Bill

Trimmer line breaks for a variety of reasons. Make sure you’re following your trimmer’s specific guidelines. Using the full length of the line will cause the line will break off, the only part of the trimmer that does any of the work is the very tip of the line.
Another reason the line breaks often, if the trimmer touches an object such as the concrete walk or a tree or anything else too close to the head itself, then the line will break off and slip back into the head assembly, causing the user to take apart and restring. Also trying to cut weeds that are very thick and fast will cause the weeds to get in too far into the line and that will also break the line. Just make sure that you move very slowly when cutting large weeds. It will get you done much faster.
Lastly, make sure that you feed the line out often, waiting to feed the line out until it is too short, will also cause problems. We hope this will help you to solve your problem and you will have a more enjoyable user experience.
Should you have any further questions or warranty needs, contact us through chatbot on www.greenworkstools.com or call Greenworks Pro toll-free helpline 1-855-345-3934. We would like the opportunity to speak with you to see if we can find a solution.