OS X Yosemite - Problems mirroring (HDMI or VGA cable)

[marieloy]

Hi, I have a MacBook Air with OS X Yosemite and I can't mirror my computer on a TV (HDMI cable) ou a projector (VGA cable). First problem: when I plug the cable, it doesn't connect automatically. Second problem: all the tutorials I read ask to go to "System Preferences" --> "Displays" --> "Arrangement". I turns out my computer doesn't have this "arrangement" button on display settings, just the "display" and "color" buttons. I've tried everything and don't know what to do now. I know the problem isn't the computer or the cables because a unknown men was able to connect my computer, I just didn't see how and I can't find him again. Please, help me.

 

[SkimMilk168]

1) all cables working?
2) all adapters working?

If you are sure these are all working, then try this:
- shutdown MBA
- Hook up HDMI to TV and MBA.
- on your TV, switch to the HDMI input
- power on your MBA

See if this helps the connection via HDMI.

Do the same for VGA if you want to test.

Reason for powering down all devices then turning on the TV/projector first is to help with the auto negotiation between the 2 devices. Sometimes our machines are not able to talk / see each other properly, resulting in this situation.
Let us know if this helps.