Public bug reported: It seems to have happened after I installed Kubuntu Desktop in Ubuntu 16.04. From then on installing anything through Synaptic Package Manager, Ubuntu Software Store or apt results in postfix errors.
ProblemType: Package DistroRelease: Ubuntu 16.04 Package: postfix 3.1.0-3 ProcVersionSignature: Ubuntu 4.4.0-38.57-generic 4.4.19 Uname: Linux 4.4.0-38-generic x86_64 NonfreeKernelModules: nvidia_uvm nvidia ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 Date: Thu Oct 20 19:14:43 2016 ErrorMessage: subprocess installed post-installation script returned error exit status 75 EtcMailname: steverobbins-Ubuntu15.04 Hostname: steverobbins-Ubuntu15.04 InstallationDate: Installed on 2015-12-01 (325 days ago) InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422) PostconfMydomain: 04 PostconfMyhostname: steverobbins-Ubuntu16.04 PostconfMyorigin: /etc/mailname RelatedPackageVersions: dpkg 1.18.4ubuntu1.1 apt 1.2.12~ubuntu16.04.1 ResolvConf: # Dynamic resolv.conf(5) file for glibc resolver(3) generated by resolvconf(8) # DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE OVERWRITTEN nameserver 127.0.1.1 SourcePackage: postfix Title: package postfix 3.1.0-3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 75 UpgradeStatus: No upgrade log present (probably fresh install) ** Affects: postfix (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-package need-duplicate-check xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1635759 Title: package postfix 3.1.0-3 failed to install/upgrade: subprocess installed post-installation script returned error exit status 75 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/postfix/+bug/1635759/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs