I'm sorry, but I can't reproduce this issue in a clean 18.04 chroot: aptitude is installed at version 0.8.10-6ubuntu1, too, and has a dependency on libsigc++-2.0-0v5 (version 2.10.0-2 installed as in your case) which contains /usr/lib/x86_64-linux-gnu/libsigc-2.0.so.0.
And aptitude works for me. Can you run "dpkg -C libsigc++-2.0-0v5" to check if all files of that package are there and undamaged? ** Changed in: aptitude (Ubuntu) Status: Invalid => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1851925 Title: Fresh install of aptitude is broken - missing dependency? To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/aptitude/+bug/1851925/+subscriptions -- ubuntu-bugs mailing list firstname.lastname@example.org https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs