This just started happening after a recent reboot of my 16.04 box. It had been run running for about a month with reboots and everything with no problem. I could use a windows box and VNC in and all was well.
I hadn't rebooted for about a month until this morning with no changes other than apt-get upgrades. Now I when I connect it is very slow over VNC.
If I reboot while a monitor is plugged in, all is well.
None the less, I would like remote desktop to work when booted without a monitor attached (working meaning not painfully slow).
I'm not sure why it stopped working as I never had monitor on it after initial setup and has been just fine. But one of those apt-get upgrades seem to have changed something.
Thoughts?