I did some research on this and they were saying Press Command+F2 So did I ! But here are the issues I saw with this method:

The youtube video that was previously running on iMac continued to run, I could hear its vocie but no picture. I want iMac programs to stop running if possible.

The Mouse and Keyboard on the iMac stopped working and I had to use MacBook's Mouse and keyborad which is ridiculous!

What I want to achieve:

  • iMac turn into Display for MacBook Pro.
  • Be able to use iMac mouse and Keyboard.

What I have:

  • Thunderbolt Cable to connect to MacBook and iMac
  • iMac model: These new thin 27" ones.
  • Macbook model: 15" retinal display ones.

Basically when I am at home and want to work on my work laptop- which is this MacBookPro one - I want to be able to connect it to my iMac and use that as display.

2 Answers 2


Ok got it working:

  1. turn off both devices.
  2. connect them with thunderbolt cable
  3. turn on MacBookPro AND keep holding the "T" key on its keyboard. You will see it will go to a disk mode with some thunderbolt icon showing on its screen.
  4. Turn on your iMac AND keep holding the OPTION key on its keyboard. You will see it will show you some hard disks on the display. Pick the one that is for the MacBookPro.
  5. Done! Now Nothing from iMac is running in the background, iMac's peripherals are working for MacBookPro AND EVEN better: you are using CPU Power and RAM of your iMac to run MacBookPro.

NOTE: to turn off, don't just unplug the thunderbolt cable, first shut down the computer, then unplug the cable.

  • A few things about step 4. First, you need to press the OPTION key on the iMac keyboard almost immediately after turning on the power of the iMac. I found out it works too if you start pressing the OPTION key before powering up. And keep OPTION pressed until the hard disks are displayed on the iMac screen. Second, both hard disks had the exact same name Macinthosh HD. With me the MacbookPro one is yellow and is on the right side. Can you be more specific on the shut down part (which computer)? I mean is it like: 1. Shut down iMac, 2. shutdown MacBookPro, 3. unplug thunderbolt cable? Apr 20, 2015 at 20:31

So they are not going to happen.

First of all the mechanism that turns the iMac to a thunderbolt display that works only with Mac is not documented, so we're in the dark. The applications running on iMac seemed to not know what happened and continued to run.

Second, since your bluetooth devices are connected to your iMac, you can't connect them to your MacBook unless you disconnect them from the iMac.

Lastly, judging from your needs, the easiest way to do them is to sync your work. That way you can use iMac's keyboard and mouse, and have it behave normally.

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