Comment 1 for bug 1872485

systemd-timesyncd is conflicting with virtualbox-guest-utils but virtualbox-guest-utils isn't providing time-daemon... debian/control in virtualbox contains:

Package: virtualbox-guest-utils
Architecture: amd64 i386
Depends: adduser,
         pciutils,
         virtualbox-guest-dkms (= ${source:Version}) | virtualbox-guest-source (= ${source:Version}) | virtualbox-guest-modules,
         ${misc:Depends},
         ${shlibs:Depends}
#Conflicts: time-daemon, ntp
#Provides: time-daemon
#Replaces: time-daemon