Screen sharing redraw problem

I've worked out a solution...

If you run ScreenResX on your MacMini and set up a resolution profile to match your local machine (ie. MacBook Air - 1366 x 768) then the remote res is the same as the local res and there is no graphical corruption.

Screen Sharing will be much more responsive too as it doesn't have to scale the pixels on the fly to your remote machine.

This solved ALL of my Screen Sharing graphic corruption problems.

Here's an example of the profiles I set up in ScreenResX on my MacMini server to match my client screens...

@DJ DEBRIS,this is dangerous. Changing resolution inside a VNC session will cause ****!

Just get the display adapter from Apple or a cheaper one from Monoprice, and put a 100 ohm resistor between the appropriate pins. This will force the OS to load the display drivers. You can find a detailed explanation by googling it. In any case, screen redraw, display lag, resolution issues all gone. Works like a champ in screen sharing now, and I can set any resolution I like. No configuration acrobatics or extra software required. A coworker is using the same solution for a headless mini with excellent results.

agent-p, which mac mini did you build a dongle for successfully? I shoved a 100 ohm resistor in pin 1 & 6 and it had no effect on mac mini late 2012 model with a mini-DisplayPort to VGA adapter. I still get graphics problems through VNC. If I connect it to a real monitor, display problems go away. Using Mountain Lion 10.8.4. I also tried adding 56 ohm resistors (what I had around) between pins 2&7 and 3&8 but it didn't help. Supposedly 50 to 150 ohm should work.

I tried "Download Air Display Host Software" at getairdisplay.com and after installing and rebooting, my VNC graphics problems were different, but still there. Things were slow and the mouse had a trail of duplicate mouse pointers. Display preferences didn't show any airplay devices available so I didn't see how to do anything additional to activate the driver.

Then I decided to connect my mini-displayport to VGA dongle to the VGA connector on my main monitor. Despite having the monitor connected to another computer via its DVI port and showing video from that other computer, the Mac still sees it and identifies the monitor by name in display preferences! Connecting the monitor like this fixes all VNC graphics problems.

To anyone who can't get the hacked dongle to work or use a spare port on a monitor to fix the problem, there's also a $60 dongle called "Gefen DVI Detective N" on Amazon that you can program to repeat the signal from whatever the last monitor you hooked it up to such that anything you connect the dongle to will believe the dongle is that last monitor.

I've also read that Mavericks improves this problem but it's not clear from what I've read if it solves it entirely (certainly not for everyone). I tried Mavericks briefly on a different machine but it had too many problems like broken file sharing to Windows and inability to mount a time machine disk automatically after waking from sleep, so I don't want to use it on the mac mini.

Works on a 2010 Mac Mini server, and a brand new 2013 mini both running mountain lion. Haven't tried it with VNC, but Apple screen sharing works fine from my iMac running Mavericks and my Air running Mountain Lion

Avatron Get Air Display fixed it for me thanks.

BUT it makes the Mac think there are 4 displays - so regular ScreenSharing doesn't work - need to have the PAID Apple Remote Dekstop.

@DJ DEBRIS

This worked perfectly for me! This has been a thorn in my side for LONG time ... Thanks for the post!!!

They actually make headless adapters now. MUCH easier than making one myself.

The NewerTech one that macy1892 referenced looks good.

I just got some adapters for the HDMI port on a MacMini that seem to be working well, and are only $15 each.

$15 US - http://www.amazon.com/exec/obidos/ASIN/B00FLZXGJ6/jbenterprises/

$18 Canadian - http://www.amazon.ca/exec/obidos/ASIN/B00FLZXGJ6/johannsbookst-20/

I guess the mini-DisplayPort adapter is good for other systems, but the tiny HDMI does not take up as much space on the back of the machine.

You'd almost think this was a joke, right? "it just works", that is, if you install a dongle so that the driver can load. Gosh. Apple, you're really not gonna fix this, are you?

This still on-going bug (a year later) in OSX is not likely to be fixed the two not great work arounds are:

1. Make a build a faked dongle to trick OSX to by pass this bug.
http://apple.stackexchange.com/questions/152354/screensharing-slow-even-over-gig abit-ethernet

2. Turn off OSX screen sharing and install your own VNC server

http://www.tightvnc.com/

https://www.realvnc.com/download/

I have also seen some people resolve this by buying OSX Server ( $20 ) from the app store.