After backing up computer get an error. Details lists message "Out of Space" for some larger video files even though there is plenty of space on my backup drive. Using Norton 360 on Windows 11
Have you been backing up to this external drive for some time? Or is this your first time backing up to this drive.
Be sure you have your backup set set to backup to your external drive and not your online/cloud backup drive, and that that drive has been mapped to a drive letter.