I have a Macbook Pro 17-inch Early-2011 model. It is running 10.7.5 and no matter what I do, it does not want to output to an extra display using Thunderbolt (and a Mini Display port to VGA adapter).

Is there anything I can do for my Macbook to detect the extra display? I have tested with a fairly old Fujitsu LCD and a brand new LG one. None of them are detected in Displays.

I have tried:

  • activating display in Clamshell mode by sleeping (closing lid) and waking MBP up with external keyboard -> NOTHING
  • download GFXStatus and switching to discrete mode -> NOTHING
  • tried booting into Clamshell mode -> NOTHING
  • downloaded all available firmware updates and software updates for Thunderbolt, every time being reminded that I either need 10.8 installed or an earlier version of Lion (10.7.4).

Your help is appreciated.

  • Do you have more than one VGA cable? That could be the culprit; or perhaps a faulty MDP adapter. Can you try the cable and adapter on a different computer? Jul 4, 2013 at 14:26
  • Can you tell us (or show) what mini display to VGA are you using?
    – Ruskes
    Jul 4, 2013 at 16:31
  • I have tried both a generic and Apple Mini Displayport to VGA in the Thunderbolt port, nothing happens. The screen just keeps saying "No signal". My MBP's power cable is plugged in. Though the Apple MDP to VGA adapter does work, as it is a colleague's. Jul 5, 2013 at 7:23

1 Answer 1


Based on your hard labor so far :) and that the problem is not the cable.....it is time to try the:

1) Restart the computer in Safe Mode with display attached (shut down and restart while holding down shift key).

The display will show up without distortion.

2) Change the display to desired preferences (dimensions and refresh rate).

3) Restart computer.


Since you mentioned the messages during the download, lets consider following.

From Apple:

This could occur when a self-powered Thunderbolt device (other than a directly-connected Thunderbolt display) is connected to a Thunderbolt port while installing the update.

To resolve this issue:

Shutdown your computer.
Disconnect all Thunderbolt devices.
Wait 10 seconds.
If you are using a Mac mini with a Thunderbolt display, reconnect the Thunderbolt display directly to your computer via the Thunderbolt port. Do not connect other Thunderbolt devices at this time.
Restart your computer.
If the Thunderbolt Firmware Update 1.2 is offered, download and install it and restart your computer when asked. If the Thunderbolt Update is not offered, the update has installed correctly.
Reconnect all Thunderbolt devices.

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