Like Toohip in https://community.norton.com/en/forums/selected-folderfile-backups, I have the same problem. I didn't understand how to select folders and files to back up the first time, and ended using almost all of my space. I since figured out how to properly select files and folders to back up, but I have no space left available, and when I try to delete the first back up set, and start over again with a new backup set, I'm told that I can't delete the first set. See the attached png file. How do I fix this?