I had a problem, whenever I turned my mac on Steam would tell me that I didn’t have an internet connection but immediately clicking on retry would connect successfully.
So the problem was that Steam doesn’t give the computer time to get a wifi connection or even silently retry after a second or two before notifying the user.
How to fix this?
go to Applications -> Automator
Find run Applescript
and type this script
tell application "Steam"
Save it as StartSteam or any other name you deem suitable (I saved it in my home folder) and also be sure to save the script as an application rather than a .workflow
Now in Preferences -> Accounts -> Login Items add the script and remove Steam from the list.
Now Steam will start a little later than it used to and will allow your mac to gain a wifi connection before it logs in.