Public bug reported: "This can be caused by: * Upgrading to a pre-release version of Ubuntu * Running the current pre-release version of Ubuntu * Unofficial software packages not provided by Ubuntu"
None of this applies. I *did* have unofficial software packages when I first got this error, but I removed all of them, I believe (removed everything under "Obsolete ... Packages" in aptitude). Still getting the error. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: ubuntu-release-upgrader-core 1:16.04.17 ProcVersionSignature: Ubuntu 4.4.0-47.68-generic 4.4.24 Uname: Linux 4.4.0-47-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 CrashDB: ubuntu CurrentDesktop: LXDE Date: Sat Nov 12 20:12:11 2016 InstallationDate: Installed on 2016-02-21 (265 days ago) InstallationMedia: Lubuntu 15.10 "Wily Werewolf" - Release amd64 (20151021) PackageArchitecture: all SourcePackage: ubuntu-release-upgrader UpgradeStatus: Upgraded to xenial on 2016-11-13 (0 days ago) mtime.conffile..etc.update-manager.release-upgrades: 2016-08-21T21:46:34.658796 ** Affects: ubuntu-release-upgrader (Ubuntu) Importance: Undecided Status: New ** Tags: amd64 apport-bug dist-upgrade xenial -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1641373 Title: "An unresolvable problem occurred while calculating the upgrade" to Yakkety To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1641373/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs