Had an issue trying to recover from a failed upgrade.  Apt would complain about dependencies, suggested running apt-get install -f.

Running apt-get install -f would still fail.  It showed a conflict with the systemd1.service, ended up renaming the file with the following command

sudo mv /usr/share/dbus-1/system-service/org.freedesktop.systemd1.service{,bak}

and reran

sudo apt-get install -f

after that I was able to rerun the upgrade and finish

sudo apt-get upgrade