Mountain Lion - Screen share over WIFI

I'll chime in as one more who can't get screen sharing to work on Mtn Lion on my wifi network.

I use it heavily on my network and it works great in connecting to older computers, but the Mtn Lion computers cannot screen share with one another. If they do eventually connect, the delay makes it unusable.

Computers running older versions of OS X can connect to the Mtn Lion computers and screen share perfectly. It's only my Mtn Lion to Mtn Lion screen sharing that is failing to work.

I've run utilities, I've turned off iCloud, I've rebooted my router and tried every other trick I can think of or discover on line. No luck.

Screen sharing in Mountain Lion has apparently been broken.

A couple of more things I've found that I would like to add.

1) Using messages on both 10.8.2 machines i am able to use the bonjour accounts on to share one screen with the other. Interestingly, this doesn't have the same slowness issues we've been discusssing in this thread. Obviously the difficulty with this messages approach is that the machine sharing its screen must accept the invitation from the machine trying to share it. It defeats the purpose and if the machine being shared is headless it becomes impossible.

2) I previously used two machinces 10.8.2, both logged into the same icloud acct w/ back to my mac turned on, over the internet and that worked very well and was actually faster than some local network screen sharing i've experienced.

actually i was wrong. you can setup messages to auto accept screen sharing requests.

go to preferences

go to alerts

from event drop down choose "Invitation to Share My Screen"

check the "Run an AppleScript" box

choose "Auto Accept.applescript" from the drop down

also this is for all buddies who request to share your screen, which could lead to auto accepting of screen sharing requests when you don't want it.

the more specific way to do it would be to choose your buddy in the buddy list and enter cmd-I to show the info for the buddy. select the alerts panel and follow the previous instructions to set it up just for this one buddy.

for some reason it doesn't work for bonjour accounts on a per user basis for me. i have to use the version that accepts all requests globally. however if you use an apple id that no one else is buddies with i suppose there won't be much of a risk of anyone trying to contact you on that account.

also, credit to this person on how to do this, I didn't figure it out on my own.

http://www.youtube.com/watch?v=b905lm4AeAU

Gary,

Thanks for your post. I was having the same problem, accessing iMac running 10.8.2 from MacBookPro running the same. Screen response was horrible, even over my wired LAN since updating to Mountain Lion. I checked my Screen Sharing Preferences and adjusted them to your suggested settings and the restarted Screen Sharing session. It is much much better... not back to where it was or should be, but it is no useable.

Thanks again!

Hi all,

I have been having the same problem, It didnt take me long to figure out what the problem is and how to fix it, if you run your remote mac headless (no montor attached), screen sharing will be laggy straight away and will get worse within about a minute and in my opinion is to slow to use, as soon as plug a montior into the remote machine problem disapears and screen sharing is perfect, this is completely repeatable and I recommend everyone here try this first, I gather it has something to do with the GPU/iGPU in the machine you are remoting into.

My Setup

rMBP with Thunderbolt display as the client and a Mac Pro (with no monitir normally) as the host, tested over WiFi and over gigabit connection.

Mac Pro with no montor = lag and unusable screen sharing with every VNC client/server known to man, even ARD

Mac Pro with elcheapo montor attached = super fast screen sharing with every client/server including ARD

Both machines are running ML 10.8.2

Im about to make a VGA/DVI dongle with 3 100ohm resisters and see if this is enough to trick the GPU on the Mac Pro into thinking it has a monitor plugged into it, Ill post back here once I have tried it.

Cheers from AU

Hey Kung-Foo-Kamel and LyndyB,

Unfortunately this didn't resolve the issue for me. I've tried it both with my mac mini not headless and rebooting the machine with the display plugged in and starting screen sharing from that point, but also with macbook to macbook screen sharing connections using the internal displays (so obviously not headless). I get the unusably slow response in both cases.

Changing the screen sharing settings did nothing for me. Actually, mine were already in the suggested settings, but I changed them and tested and changed them back to the suggested settings and tested. None of this resolved my issue.

The only thing that's worked for me is using messages to screen share in the way I described above.

That's a shame it doesn't work for you, It's definitely a repeatable issue with my setup, this is the first time I have used Apple Remote Desktop as my Mac Pro was running windblows as a server operating system and I was using RDP to connect, RDP appears to be much quicker than VNC, I'm not sure what VNC was like before Mountain Lion but it is usable but still has some lag over Ethernet and a little more over WiFi-N but without a screen plugged in its totally useless.

Im still having the odd issue were screen sharing completely stuffs up and freezes, I usually have to quit the app from the dock and fire it back up, this is random and has only happened a few times, the other issue is you can't make it scale to full screen like MS RDP, it's a huge drawback as I use a Thunderbolt Display with a high resolution and the Mac Pro headless only does 1650 max and worse with the screen plugged in, this results in a little window in the middle of my 27" display, this is quite awful to use, MS actually got something right with there RDP, I'm starting to regret upgrading my server from MS to OSX ML server

For anyone that may be experiencing issues with screen sharing lockups I managed to fix mine, I made sure that all third party VNC client/server software was removed, I then re-installed Apple remote desktop on both client and server machine, updated to v3.6.1, disabled screen sharing/remote management then reactivated remote management, this appears to have fixed all issues, except the headless part, I still require a screen connected.

I still think the client could be be better, definitely needs proper full screen scaling and could do with a little less lag, I have noticed when I'm transferring data to the server the client appears to lag more, I think it could do with better QOS control as the VNC service should have total priority over network bandwidth and CPU usage, file transfers over gigabit lan should not impact screen sharing as it never impacted MS RDP.

Hopefully the info I have provided in these posts helps someone fix there issues, I also hope one of the next updates from Apple will address these issues as Apple is nearly there on being a better solution than Microsoft..finally.

Cheers

KFK

I wish the HDMI was the answer but it does make any difference to me. I have the latest Mac Mini (2 weeks old) it's conencted by HDMI to my TV but I still have the issue.

When I first posted to this thread I was using an older Mac Mini with the display port connected to the same TV via the Apple VGA adaptor - Screen sharing had worked fine with Snow Leopard and Lion - but broke with Mountain Lion.

On my new Mac Mini the screen sharing remains unusable even if the TV is on and I can see the real display, the screen sharing remains broken.

I was having the same problem and I can confirm that the slowness is caused by not having a monitor plugged in and On, as soon as I turned on my TV everything went back to normal. I hope apple comes out with a fix soon this is definatly a bug.

Don't run Screen Sharing over a 5 GHz wi-fi network, make sure you run it through a 2.4 GHz SSID. This is the real problem with Screen Sharing and my wife figured it out 🙂

This has been driving me crazy since mountain lion came out. None of the monitor/no monitor stuff was applicable to me since I was trying to connect to an iMac from my macbook pro.

I swtiched one of my systems over to the 2.4 SSID and screen sharing started working like a champ. I have no idea why that is. I didn't have to take both of them to 2.4, just one of them. In this case I put the client on 2.4.

Hopefully Apple with get their act together and fix this for everyone.

Please pass my thanks to your wife.