Screen Sharing is broken in macOS 10.13.4

Have you tried any of these?

A Troubleshooting Procedure that may Fix Problems with macOS El Capitan or Later

You should try each, one at a time, then test to see if the problem is fixed before going on to the next.

Be sure to backup your files before proceeding if possible.

1. Shutdown the computer, wait 30 seconds, restart the computer.
2. Disconnect all third-party peripherals.
3. Resetting your Mac’s PRAM and NVRAM
4. Reset the System Management Controller (SMC)
5. Reset your Startup Disk and Sound preferences.
6. Start the computer in Safe Mode. Test in safe mode to see if the problem persists, then restart normally.
7. Use Apple Hardware Test to see if there is any hardware malfunction.
8. Repair the disk by booting from the Recovery HD. Immediately after the chime hold down the Command and R keys until the Utility Menu appears. Choose Disk Utility and click on the Continue button. Select the indented (usually, Macintosh HD) volume entry from the side list. Click on the First Aid button in the toolbar. Wait for the Done button to appear. Quit Disk Utility and return to the Utility Menu. Restart the computer from the Apple Menu.
9. Repair permissions on the Home folder: Resolve issues caused by changing the permissions of items in your home folder.
10. Create a New User Account Open Users & Groups preferences. Click on the lock icon and enter your Admin password when prompted. On the left under Current User click on the Add [+] button under Login Options. Setup a new Admin user account. Upon completion log out of your current account then log into the new account. If your problems cease, then consider switching to the new account and transferring your files to it - Transferring files from one User Account to another.
11. Download and install the OS X El Capitan 10.11.6 Combo Update or 10.12.6 Combo Update or Download macOS High Sierra 10.13.4 Combo Update as needed.

I had the same problem as david.allie trying to VNC to my Mac Pro from my 2015 MPB. Oddly enough my 2011 MPB could access the Mac Pro screen sharing.

After reading his post I discovered this "unknown to me" NEW Remote Desktop update that was sitting there. Installed the update and rebooted the Mac Pro and VNC (Screen Sharing) is working again using the 2016 MPB. In retrospect, looking at my 2011 MPB, I had not yet installed the 2018-001 security update; which is why VNC was working with it.

Mac Pro 3,1 (Early 2008) OS 10.11.6

Macbook Pro 13,3 (2016) OS 10.13.4

Macbook Pro 8,3 (2011) OS 10.13.4

So I too use a headless MacMini for certain functions and installing 10.13.4 has caused a lot of issues with Screen Sharing. The symptoms I get are that I can connect, but the mouse and keyboard won't function on the remove screen. A way around this is t go to "View" in Screen Sharing on my MacBook and switch the view quality from Adaptive to Full or vice-versa, this brings the functionality back. Sometimes the scaling is all screwed too, so this needs to be changed.

What's interesting is that I setup a new user on the client-side and with that I get no issues at all, so it's some kind of legacy setting that's manifesting the issue. I've been searching to see if there are some plists that can be removed that might give a reset, but so far no luck.

I had the same issue, VNC not working in high sierra.

After reading a lot and a lot of testing, this is what helped me and worked:

- In Preferences/Security/Firewall/Firewall options, delete all entries as far and possible.

- You may end up with a few entries, such as “Screen Sharing”.

- In Prefgerences, disable all these services

- In Firewall options, check that all entries are gone.

- Reboot.

Now re-enable screen sharing and other services as required. You may be asked whether you want to allow specific service through the firewall. Enable this at least for screen sharing, launchd, kcd.

Worked for me.

This is not a solution if Remote Desktop is not installed.

I am having the same trouble as david.allie

Same problem. Can't VNC to two headless MacMini's from MBP just updated and now running 10.13.4. TeamViewer only solution (for me) until Apple fixes this.

The same for me too.

Screen Sharing works between two r-Macbook Pro 2015, but not between r-Macbook Pro 2015 and Macbook pro 2011: I have only the sound, without the video.

Same issue here trying to connect to my old 2009MBP using my 2017MBP, it doesn't work anymore since 10.13.4..

Apparently this is a well known issue, see here:

https://help.duetdisplay.com/faq/305404-macos-10-13-4-support

so... wait and see (will be solved soon hopefully!)

OS X 10.13.5 resolved my problem with Screen Sharing locking up in Full Screen mode from my late 2013 MacBook Pro (Retina). The problem started when OS X 10.13.4 was installed.

macOS 10.13.5 solved the issue for me too. (appeared also with 10.13.4)