If you are having network issues and viewing and connecting blackout in ARD this is what I figured out:
So, I was having the same black out problems all of you are having. I work at a school and manage 350 Macs ranging from brand new to 5 years old. When upgrading to 10.9.4 and ARD 3.7.2 all my labs when trying to view them in ARD where black and when clicking on them a dialog box would pop up and then an network error saying :
"Please make sure that Screen Sharing (in the Sharing section of System Preferences) is enabled on the computer to which you are attempting to connect. Also make sure your network connection is working properly".
After making sure all the setting had been set right and rebuilding our lab images from scratch and still having the problem a colleague and I started to test every single application we use in our build to see if it was either an application or hardware problem. Every application we installed we would immediatly restart and check ARD to see if we could see and control.
On a side note we could get the computers to show up in safe mode therefore bypassing all basic applications (holding shift on start up).
With all this said the application that was the culprit was a version of MCAfee Antivirus which was required by the institution:
This is the name of the dmg:
EPM210-RTW-1085.dmg
Take a look at your antivirus!
