So your system is obviously not an 18.04 default installation from scratch - otherwise you would have netplan.io installed and this folder and file "/etc/netplan/01-netcfg.yaml" will exist on your system.
There is no known way to me to install an 18.04 system without having netplan (initially) as default. Did you have removed netplan manually from that installation? Or is your 18.04 system and upgrade from an older Ubuntu release (like 16.04 or 17.10)? If it's an 18.04 installation from scratch please provide the installation logs. They are during the installation available at /var/log/* and after the installation still available at /var/log/installer/* -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1772859 Title: Network Manager is not able to manage the devices on Ubuntu 18.04 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1772859/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
