$ sudo apt-get update && sudo apt-get dist-upgrade Hit:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease Hit:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease Get:3 http://security.ubuntu.com/ubuntu xenial-security InRelease [102 kB] Fetched 102 kB in 0s (225 kB/s) Reading package lists... Reading package lists... Building dependency tree... Reading state information... Calculating upgrade... The following packages were automatically installed and are no longer required: linux-headers-3.13.0-116 linux-headers-3.13.0-116-generic linux-headers-4.4.0-75 linux-headers-4.4.0-75-generic linux-headers-4.4.0-77 linux-headers-4.4.0-77-generic linux-headers-4.4.0-78 linux-headers-4.4.0-78-generic linux-headers-4.4.0-79 linux-headers-4.4.0-79-generic linux-headers-4.4.0-81 linux-headers-4.4.0-81-generic linux-headers-4.4.0-83 linux-headers-4.4.0-83-generic linux-headers-4.4.0-87 linux-headers-4.4.0-87-generic linux-headers-4.4.0-89 linux-headers-4.4.0-89-generic linux-headers-4.4.0-92 linux-headers-4.4.0-92-generic linux-headers-4.4.0-93 linux-headers-4.4.0-93-generic linux-image-3.13.0-116-generic linux-image-4.4.0-75-generic linux-image-4.4.0-77-generic linux-image-4.4.0-78-generic linux-image-4.4.0-79-generic linux-image-4.4.0-81-generic linux-image-4.4.0-83-generic linux-image-4.4.0-87-generic linux-image-4.4.0-89-generic linux-image-4.4.0-92-generic linux-image-4.4.0-93-generic linux-image-extra-3.13.0-116-generic linux-image-extra-4.4.0-75-generic linux-image-extra-4.4.0-77-generic linux-image-extra-4.4.0-78-generic linux-image-extra-4.4.0-79-generic linux-image-extra-4.4.0-81-generic linux-image-extra-4.4.0-83-generic linux-image-extra-4.4.0-87-generic linux-image-extra-4.4.0-89-generic linux-image-extra-4.4.0-92-generic linux-image-extra-4.4.0-93-generic Use 'sudo apt autoremove' to remove them. The following packages will be upgraded: curl distro-info-data initramfs-tools initramfs-tools-bin initramfs-tools-core libcurl3 libcurl3-gnutls libicu55 libpam-systemd libsystemd0 libudev1 linux-firmware postfix systemd systemd-sysv udev wpasupplicant 17 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 59.8 MB of archives. After this operation, 40.5 MB of additional disk space will be used. Do you want to continue? [Y/n] Get:1 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libsystemd0 amd64 229-4ubuntu20 [205 kB] Get:2 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libpam-systemd amd64 229-4ubuntu20 [115 kB] Get:3 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 systemd amd64 229-4ubuntu20 [3,783 kB] Get:4 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 udev amd64 229-4ubuntu20 [992 kB] Get:5 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libudev1 amd64 229-4ubuntu20 [54.9 kB] Get:6 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 initramfs-tools all 0.122ubuntu8.9 [8,616 B] Get:7 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 initramfs-tools-core all 0.122ubuntu8.9 [42.7 kB] Get:8 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 initramfs-tools-bin amd64 0.122ubuntu8.9 [9,632 B] Get:9 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 systemd-sysv amd64 229-4ubuntu20 [12.4 kB] Get:10 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 distro-info-data all 0.28ubuntu0.5 [4,224 B] Get:11 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 curl amd64 7.47.0-1ubuntu2.4 [139 kB] Get:12 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libcurl3-gnutls amd64 7.47.0-1ubuntu2.4 [184 kB] Get:13 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libicu55 amd64 55.1-7ubuntu0.3 [7,658 kB] Get:14 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 libcurl3 amd64 7.47.0-1ubuntu2.4 [186 kB] Get:15 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 linux-firmware all 1.157.13 [44.4 MB] Get:16 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 postfix amd64 3.1.0-3ubuntu0.1 [1,152 kB] Get:17 http://mirrors.digitalocean.com/ubuntu xenial-updates/main amd64 wpasupplicant amd64 2.4-0ubuntu6.2 [902 kB] Preconfiguring packages ... Fetched 59.8 MB in 1s (45.5 MB/s) (Reading database ... 527666 files and directories currently installed.) Preparing to unpack .../libsystemd0_229-4ubuntu20_amd64.deb ... Unpacking libsystemd0:amd64 (229-4ubuntu20) over (229-4ubuntu19) ... dpkg: unrecoverable fatal error, aborting: fork failed: Cannot allocate memory E: Sub-process /usr/bin/dpkg returned an error code (2) $ sudo service apache2 stop $ sudo apt-get update && sudo apt-get dist-upgrade Hit:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease Hit:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease Hit:3 http://security.ubuntu.com/ubuntu xenial-security InRelease Reading package lists... Done E: dpkg was interrupted, you must manually run 'sudo dpkg --configure -a' to correct the problem. $ sudo dpkg --configure -a Processing triggers for libc-bin (2.23-0ubuntu9) ... $ sudo apt-get update && sudo apt-get dist-upgrade Hit:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease Hit:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease Hit:3 http://security.ubuntu.com/ubuntu xenial-security InRelease Reading package lists... Reading package lists... Building dependency tree... Reading state information... You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: E: Unmet dependencies. Try using -f. $ sudo apt-get update && sudo apt-get dist-upgrade Hit:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease Hit:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease Hit:3 http://security.ubuntu.com/ubuntu xenial-security InRelease Reading package lists... Done Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: E: Unmet dependencies. Try using -f. $ sudo apt-get update Hit:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease Hit:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease Hit:3 http://security.ubuntu.com/ubuntu xenial-security InRelease Reading package lists... Done $ sudo apt-get dist-upgrade Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: E: Unmet dependencies. Try using -f. $ sudo apt-get upgrade Reading package lists... Done Building dependency tree Reading state information... Done You might want to run 'apt-get -f install' to correct these. The following packages have unmet dependencies: E: Unmet dependencies. Try using -f. $ sudo apt-get -s -f install Reading package lists... Done Building dependency tree Reading state information... Done Correcting dependencies... Done The following packages were automatically installed and are no longer required: linux-headers-3.13.0-116 linux-headers-3.13.0-116-generic linux-headers-4.4.0-75 linux-headers-4.4.0-75-generic linux-headers-4.4.0-77 linux-headers-4.4.0-77-generic linux-headers-4.4.0-78 linux-headers-4.4.0-78-generic linux-headers-4.4.0-79 linux-headers-4.4.0-79-generic linux-headers-4.4.0-81 linux-headers-4.4.0-81-generic linux-headers-4.4.0-83 linux-headers-4.4.0-83-generic linux-headers-4.4.0-87 linux-headers-4.4.0-87-generic linux-headers-4.4.0-89 linux-headers-4.4.0-89-generic linux-headers-4.4.0-92 linux-headers-4.4.0-92-generic linux-headers-4.4.0-93 linux-headers-4.4.0-93-generic linux-image-3.13.0-116-generic linux-image-4.4.0-75-generic linux-image-4.4.0-77-generic linux-image-4.4.0-78-generic linux-image-4.4.0-79-generic linux-image-4.4.0-81-generic linux-image-4.4.0-83-generic linux-image-4.4.0-87-generic linux-image-4.4.0-89-generic linux-image-4.4.0-92-generic linux-image-4.4.0-93-generic linux-image-extra-3.13.0-116-generic linux-image-extra-4.4.0-75-generic linux-image-extra-4.4.0-77-generic linux-image-extra-4.4.0-78-generic linux-image-extra-4.4.0-79-generic linux-image-extra-4.4.0-81-generic linux-image-extra-4.4.0-83-generic linux-image-extra-4.4.0-87-generic linux-image-extra-4.4.0-89-generic linux-image-extra-4.4.0-92-generic linux-image-extra-4.4.0-93-generic Use 'sudo apt autoremove' to remove them. The following additional packages will be installed: libpam-systemd libsystemd0 systemd Suggested packages: systemd-ui systemd-container The following packages will be upgraded: libpam-systemd libsystemd0 systemd 3 upgraded, 0 newly installed, 0 to remove and 14 not upgraded. 1 not fully installed or removed. Inst libpam-systemd [229-4ubuntu19] (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64]) [] Inst libsystemd0 [229-4ubuntu19] (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64]) [systemd:amd64 ] Conf libsystemd0 (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64]) [systemd:amd64 ] Inst systemd [229-4ubuntu19] (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64]) Conf systemd (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64]) Conf libpam-systemd (229-4ubuntu20 Ubuntu:16.04/xenial-updates [amd64])