Jtdcftul

When trying to enable "Screen Sharing" under the "Sharing" section of the system settings I can click on the "ON/OFF" slider but it will not stay set to "ON". I can set the "Sharing" slider to "ON" and the "Remote Login" slider to "ON" but not the "Screen Sharing" one. Am I missing something?

Running Ubuntu 18.04.1 LTS and have attempted this both on GNOME on xorg and GNOME Flashback

This happened to me, here is how I corrected it.

My network showed "wired-unmanaged"; to correct this, I had to do the following:

Note: If you're interested in a set of commands to copy/paste into your terminal, I'd encourage you to review these instructions first, before running the commands listed at the end of this answer.

• cd /etc/NetworkManager


• save NetworkManager.conf to NetworkManager.orig (as a backup)


• 
  

  sudo vi NetworkManager.conf

  
  
  

  Change managed=false to managed=true

  
  
  

  New file looks like this:

  
  
  

  [main]
  
      plugins=ifupdown,keyfile
  
  [ifupdown]
  
      managed=true
  
  [device]
  
      wifi.scan-rand-mac-address=no
  
  

  
  


• sudo service network-manager restart


• cd /etc/netplan


• 
  

  sudo vi 50-cloud-init.yaml

  
  
  

  Add this line just below network:

  
  
  

  renderer: NetworkManager

  
  
  

  New file looks similar to this (ensure the renderer line is indented as shown):

  
  
  

  network:
  
      renderer: NetworkManager
  
      ethernets:
  
          enp3s0:
  
              addresses: 
  
              dhcp4: true
  
  version: 2
  
  

  
  


• save


• sudo netplan apply


• I had then to restart the computer for this to be effective.


• After restart the network will now show "wired-connected"


• Then you can go to Settings » Sharing » Screen Sharing
  
  
  
  
  • You should now be able to toggle Screen Sharing to ON
  
  
  • Under Networks (bottom of dialog), toggle those ON as well
  
  
  
  

Commands

If all you're looking for is some terminal commands, and you haven't made any manual changes to the files mentioned in the instructions above, running the commands below should take care of the file modifications:

cd /etc/NetworkManager

sudo cp NetworkManager.conf NetworkManager.orig

# Change NetworkManager.conf: 'managed=false' to 'managed=true'

sudo sed -i 's/managed=false/managed=true/g' NetworkManager.conf

sudo service network-manager restart

cd /etc/netplan

# Ensure networks are managed by NetworkManager

# Whitespace in this command is important!

sudo sed -i '/^network:/a     renderer: NetworkManager' 50-cloud-init.yaml

sudo netplan apply

# Restart your machine, or uncomment one of the lines below:

#sudo shutdown -r now

#gnome-session-quit --reboot

After you run these commands, refer to the final step above to enable screen sharing.

I assume he added the ethernet and interface lines. You have to make sure the interface for your computer is used. His was enp3s0

You can run "ip a" and it will list your network devices. Will look like this:

:~$ ip a

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

   valid_lft forever preferred_lft forever

inet6 ::1/128 scope host

   valid_lft forever preferred_lft forever

2: ens2f0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

link/ether 00:1e:67:79:08:5c brd ff:ff:ff:ff:ff:ff

inet 131.192.176.162/24 brd 131.192.176.255 scope global dynamic noprefixroute ens2f0

   valid_lft 680301sec preferred_lft 680301sec

inet6 fe80::21e:67ff:fe79:85c/64 scope link

   valid_lft forever preferred_lft forever

3: ens2f1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000

link/ether 00:1e:67:79:08:5d brd ff:ff:ff:ff:ff:ff

Note in this there are 2 interfaces: ens2f0 and ens2f1

I realize you asked this question a while back. You should be able to get screen share working.

For me, I couldn't enable screen sharing, because I was running in "Wayland" (as that was the only desktop I could use). Well, Wayland doesn't support the screen sharing option. I fixed this issue by switching to the original XOrg "Ubuntu" desktop. In order to get that to work, however, there was a battle...

Check out my post on this other thread: Ubuntu 18.04 won't show desktop after login