The beta 64-bit version of the Raspberry Pi OS does not include VNC Server. A temporary workaround is to use the x11vnc server instead of the realvnc one. This has the advantage of accessing the full desktop directly with x11 forwarding like realvnc instead of starting a new desktop like tightvnc. This lacks encryption so it would probably be a bad idea to be port forwarding this, but it's a solution for those that want to access the gui while running a headless setup. [source](https://github.com/raspberrypi/Raspberry-Pi-OS-64bit/issues/3#issuecomment-636544190)
To set it up: Run sudo raspi-config and set a resolution.
To install x11vnc:
sudo apt-get install x11vnc sudo x11vnc -storepasswd yourVNCpasswordHERE /etc/x11vnc.pass sudo nano /etc/systemd/system/x11vnc.service
Add the following
[Unit] Description="x11vnc" Requires=display-manager.service After=display-manager.service [Service] ExecStart=/usr/bin/x11vnc -shared -forever -xkb -noxrecord -noxfixes -noxdamage -display :0 -auth guess -rfbauth /etc/x11vnc.pass ExecStop=/usr/bin/killall x11vnc Restart=on-failure Restart-sec=2 [Install] WantedBy=multi-user.target
Start with
sudo systemctl daemon-reload sudo systemctl start x11vnc
and make it start on boot with
sudo systemctl enable x11vnc
The vnc service will not start on the pi 4 without first setting a resolution in raspi-config. The pi 3 does not seem to need this.