2016-06-15 18:22:56 VERBOSE Sanity checking meta packages on remote system (package-sandbox) ..
2016-06-15 18:22:56 INFO Found 2 installed Linux kernel image meta packages:
2016-06-15 18:22:56 INFO  - linux-image-generic-lts-wily (4.2.0.38.31)
2016-06-15 18:22:56 INFO  - linux-image-generic-lts-xenial (4.4.0.24.14)
2016-06-15 18:22:56 WARNING You have more than one Linux kernel image meta package installed (linux-image-generic-lts-wily and linux-image-generic-lts-xenial) which means automatic package removal can be unreliable!
2016-06-15 18:22:56 VERBOSE It's probably best to stick to one Linux kernel image meta package, preferably the one that matches the newest kernel :-)
2016-06-15 18:22:56 INFO Found 1 installed Linux kernel header meta package:
2016-06-15 18:22:56 INFO  - linux-headers-generic-lts-xenial (4.4.0.24.14)
2016-06-15 18:22:56 VERBOSE Checking for removable packages on remote system (package-sandbox) ..
2016-06-15 18:22:57 INFO Found 9 installed Linux kernel image packages:
2016-06-15 18:22:57 INFO  - linux-image-3.13.0-63-generic and linux-image-extra-3.13.0-63-generic (removable)
2016-06-15 18:22:57 INFO  - linux-image-3.13.0-73-generic (removable)
2016-06-15 18:22:57 INFO  - linux-image-4.2.0-38-generic and linux-image-extra-4.2.0-38-generic (removable)
2016-06-15 18:22:57 INFO  - linux-image-4.4.0-21-generic and linux-image-4.4.0-21-lowlatency (one of 2 newest kernels)
2016-06-15 18:22:57 INFO  - linux-image-4.4.0-24-generic and linux-image-extra-4.4.0-24-generic (the active kernel)
2016-06-15 18:22:57 INFO Found 5 installed Linux kernel header packages:
2016-06-15 18:22:57 INFO  - linux-headers-3.13.0-63 and linux-headers-3.13.0-63-generic (removable)
2016-06-15 18:22:57 INFO  - linux-headers-3.13.0-88 (removable)
2016-06-15 18:22:57 INFO  - linux-headers-4.4.0-24 and linux-headers-4.4.0-24-generic (the active kernel)
2016-06-15 18:22:57 INFO Found 8 Linux kernel packages that can be removed.
2016-06-15 18:22:57 VERBOSE Command to remove packages: apt-get remove --purge linux-headers-3.13.0-88 linux-headers-3.13.0-63-generic linux-image-extra-3.13.0-63-generic linux-headers-3.13.0-63 linux-image-3.13.0-63-generic linux-image-3.13.0-73-generic linux-image-extra-4.2.0-38-generic linux-image-4.2.0-38-generic
2016-06-15 18:22:57 ERROR Refusing to cleanup kernel related packages on remote system (package-sandbox) because results can be unreliable when multiple Linux kernel meta packages are installed! You can use the -f, --force option to override this sanity check.