running 16.10, I am also running in to the problem that autoremove fails to remove old initrd files. This was greatly exacerbated by bug #798414 (https://bugs.launchpad.net/ubuntu/+source/initramfs-tools/+bug/798414). With an encrypted file system and a small boot partition, I only have space for 3 kernels. With the pace of new kernel builds, it doesn't take long to run out of space. Now that I understand the problem, it is not such a big deal, but it was very annoying to have unhelpful initramfs errors nearly every time I boot up.
running 16.10, I am also running in to the problem that autoremove fails to remove old initrd files. This was greatly exacerbated by bug #798414 (https:/ /bugs.launchpad .net/ubuntu/ +source/ initramfs- tools/+ bug/798414). With an encrypted file system and a small boot partition, I only have space for 3 kernels. With the pace of new kernel builds, it doesn't take long to run out of space. Now that I understand the problem, it is not such a big deal, but it was very annoying to have unhelpful initramfs errors nearly every time I boot up.