Screen Sharing works fine when enabled through System Preferences > Sharing. You must have the proper user access, permissions, and VNC password configured. If you have the OS X firewall running, it will block port 5900, until you uncheck Block all incoming connections in Firewall options. Once you do that, Screen sharing will magically appear, green lit as operational. There is no need to turn the firewall off.
Kind of ridiculous that Apple hasn't fixed Screen Sharing, but I found a workaround. Here's an easy step-by-step.
On the remote target computer (with the screen you want to see), go to:
1. System Preferences/Sharing
2. Click on Remote Management
3. Allow access for "All Users" (don't worry, a password is still required)
4. Click the + sign and add Users and click Select
4. Under "Options", checkmark everything on the list for full computer functionality. Click Okay.
5. Under "Computer Settings...", checkmark "VNC viewers may control screen with password".
6. Type in a password and click Click Okay.
7. See where it says, "Other users can manage your computer using the address [i.e. 10.0.1.10]." Write these numbers down.
8. Click "Show All" in the upper left hand corner to exit the Sharing window and lock in changes
On your host computer (the computer where you will click "Share Screen" in the Finder window):
1. Open a Finder window.
2. Press Command-K (or you can select the "Go" pulldown menu and select "Connect to Sever...")
3. Take the numbers you wrote down from Remote Management on the other computer and type them in following "vnc://". (So, using our example, "vnc://10.0.1.10") Click Connect.
4. It will connect and ask for the User name. It will also ask for the Password you just typed in to the Remote Management.
5. Before you hit Okay, make sure to click Remember Password.
Voilà! You have Screen Sharing restored. With the password remembered, you can now go to your Finder any time, select the target computer in your sidebar, click on "Screen Share" in the upper right hand corner of the window, and enjoy.
I seem to be having a simillar but slightly different problem. Accessing screensharing from my local network is working fine.
However, trying to acces screensharing outside my network (remotely) is not working.
I have my router set up to forward port 5900 to the mac mini's static IP address and have tested that the port is open and forwarding correctly, however whenever I try to access from the WAN IP address it times out and I get the error:
Is anyone else having this problem? I have tried everything is the 9 pages of comments, from logging out of mobileme / icloud, fixing permissions, resettin PRAM, making sure ScreenShareAgent is quit in Activity Monitor. etc etc etc.... nothing seems to be working.
I have double checked that in Screen Sharing it is turned on and allowed access, set a VNC password and allowed anyone access to request to control screen, tried seting remote management and doing the same for screen sharing there as well to no avail.
I can access screensharing when I am connecting locally to my local (router assigned) ip address, but remotly it just will not connect or even try. just keeps giving me the finger with the error above...
Updated my Net Barrier/Virus Barrier yesterday (wow what a change in interface!) and my Screen Share broke. It took a while with the new interface to figure out where it was blocking the connection. FWIW, check 3rd Party Firewall/Virus checking software for blocking if you have problems. So far most of mine have been rooted there.
Back to My Mac works in ML if you do the following:
1) System Preferences
3) Make sure Remote Management is checked
4) Under Remote Management click on Computer Settings
5) Check all the boxes (Show Remote..., Anyone may request...., VNC viewers may control.....) and put in a password inside the VNC viewers may control screen with password
6) Leave the computer information boxes empty
7) Click OK
8) Click Options under Remote Management
9) Check all 10 boxes, click 'OK'
This will enable the computer you want to watch to be reached if you previously had access under Lion but lost it under ML.
I think some of the boxes I told you to check may be left unchecked, but since this particular method worked for me flawlessly, I would suggest you do this first, and then tweak later. Now, if you didn't have access previously under Lion, that means some firewall is preventing access and you may have to tweak your router -- these instructions will not help you.
This method works over the internet or locally, and it allows ARD 3 to work properly, thank you very much. I use ARD to manage all the computers in my office, and I was pulling my hair out trying to figure why I lost access after upgrading to ML and why our new iMacs with ML would not allow remote access.
These particular instructions are probably buried somewhere underneath layers and layers of help screens explaining how to enable Back to My Mac, but Apple should have it made simple as it usually does.
Hope this works for you. Good luck and you may now upgrade to ML without fear of losing remote access through Back to My Mac.
I also believe the screen sharing issues are related to the remote machine displaying a lock screen / login window.
Every now and then, Screen sharing will not connect to a remote iMac, even though the connection worked flawlessly only a few minutes before. The remote Mac is set to never sleep but display a screen saver after a few minutes.
Experienced this issue under 10.6, 10.7 and 10.8, however, the problem would come up less frequently under 10.8. Sometimes, I was able to reconnect by killing all screensharing, ARD related processes via SSH or kickstarting ARD, yet this doesn't always help. The only way I can reconnect reliably is forcing a reboot via SSH.
Under 10.7, I could establish a screen sharing session, see a lock screen, yet the curser in the password prompt wasn't flashing and I was unable to unlock the remote Mac. Often I had to reboot. Sometimes it would cure itself after waiting 12 h or so.
Under 10.8, every now and then neither screen sharing nor ARD will connect to the remote Mac, even though it worked just a few minutes ago.
I still haven't found a reliable way to reconnect other than forcing a reboot.
In my case I set my login keychain on the remote Mac to lock after 5 minutes (via Keychain Access). I've recently had the problem that Screen Sharing doesn't get any further than the "connecting..." message. This time I went to the remote Mac, and there was a dialog box waiting for my keychain password. After entering it (ie: unlocknig the remote keychain) I could connect.
I've only recently had this problem. I think it coincides with upgrading to Mountain Lion.
This worked for me on two of my work machines. I still need to check it with my home machines
On target machine
Enable Screen Sharing > Sharing in System Preferences
It will then say: Other users can access your computer's screen at vnc://IP.ADDRESS/ or by looking for MACHINENAME in the Finder sidebar.
On local machine
In Finder > Go > Go to Folder "/System/Library/CoreServices/"
Right Click on Screen Sharing.app and select Make Alias
You'll need to enter an Admin password
Drag the Screen Sharing Alias to the Applications folder (or whereever you want it).
Rename Screen Sharing alias to Screen Sharing (optional)
Launch Screen Sharing by double clicking on it.
A dialog box with Host: will appear
Type in vnc://IP.ADDRESS/ then click Connect
You can also save this address to your Desktop (or whereever you want it) Screen Sharing > Connection > Save As...
Thanks alien_resident for your suggestion to access the machine via the VNC protocoll instead of the native Mac Screen Sharing/Apple Remote Desktop protocoll. (I am not sure though, whether clipboard sync is supported via VNC as well)
For what it's worth, I am taking a complete guess that the issues with screen sharing might also be related to problems with the grafic card driver. I am connecting to a mid-2007 iMac 24", ATI card 2600, OS X 10.8.2.
Recently, I have had issues similar to those described here.
The user interface was frozen and the machine would not accept any input.
KrzysiuTurek found out that replacing the kernel extensions for ATI grafic cards currectly included with Lion or Mountain Lion with the kernel extensions that came with 10.6.2 actually solved his issues with a freezing iMac. He is kindly providing the old files on his website http://blog.krzysztof-turek.com/imac-8-1-problem-karta-graficzna/
Kext Drop is a nice utility for replacing kernal extensions: http://www.cindori.se/#2
and an alternative to Kext Helper b7 mentioned on his website. In my case, replacing the kernel extensions worked smoothly.
It might be interesting to collect more information about the hardware you are using.
All... Im having the same issue. Two macbooks and one imac all running 10.8.2. I have tried all of these fixes.. none are working...however I want to ask are all of your connecting via a wired connection or wireless. If I connect one of our MACs to the wired LAN screen share / Remote Management works fine from the wired to the other wireless stations. However you cannot connect from the wireless to the wired conenction...