I can´t connect my MacBookPro 8.1 (Early 2011) to my projector using a "Thunderbolt to VGA Adaptor". This my second adaptor in the last 12 months and am now not sure whether the problem lies with the adaptor or my MacBook Pro. My Apple hardware report shows nothing out of the ordinary.

Is there any other reliable way to test my Thunderbolt port without plugging in any hardware or do I have do dig out more money for an adaptor that may or may not work?

  • Hardware reports shows what identified. Run AHT (Apple Hardware Test). Hold D while booting from a powered off state with the power adapter plugged in. As for the symptoms, it sound like the adapter works for a while then stops. The way to verify if it the adapter or not is to try the adapter on a different machine. That said, I believe it's the adapter not the TB port that has failed. Try the genuine Apple mDP to VGA adapter
    – Allan
    Feb 25, 2018 at 12:54

1 Answer 1


Just so you know the Thunderbolt ports on your computer have dual purpose, they are also Mini DisplayPort (ports). The cable you are using is actually a Mini DisplayPort to VGA adapter.

I've used these a fair bit at home and work, and at least the Apple ones aren't very durable in my experience, it's likely the cable has failed again. Unless you are finding other devices aren't working either, it's likely the cable.

You could book a Genius Bar appointment at an Apple Store and see if they can test the port for you with their own known good cables, that way you wouldn't have to buy another cable.

In future you could have a look at 3rd party products, StarTech adapters are pretty reliable in my experience but any brand would be worth trying.

  • of course, this doesn't answer the question ... Jan 12, 2019 at 16:57
  • @ChristopherE I would say it does by having it tested at the Apple Store where they will have a range of cables, and it furnishes the answer with information about where to get more reliable adapters. Jun 30, 2019 at 15:15

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