Gordon, oh, according to the screenshot your system seems to have both generic and lowlatency kernels installed. Is that on purpose? Does "linux-version list" output all the releases? If not, see http://askubuntu.com/q/779031/21005 . Be careful with purge-old-kernels. You might want to use its --keep option to tell it how many kernels to keep.
Gordon, oh, according to the screenshot your system seems to have both generic and lowlatency kernels installed. Is that on purpose? Does "linux-version list" output all the releases? If not, see http:// askubuntu. com/q/779031/ 21005 . Be careful with purge-old-kernels. You might want to use its --keep option to tell it how many kernels to keep.