Enabling target display mode

Thanks for all the resoltions. My issue is that it worked perfect the first time I tried my MBA 11 with my new iMac via thunderbolt to thunderbolt. However now when I try it the screen on the iMac just goes black when the MBA tries to send its screen. Nothing comes up until I press cmd+F2 again and the iMac screen comes back. I can connect a seperate screen to the iMac and it works as a second screen but the target display all of a sudden wont work. Really strange.

Many thanks Lawrence, I solved my issue thanks to your post saying it is possible to insert the TB cable the wrong way into the Imac socket. Now I understand why Display Target Mode was sometimes working and other times not working !

I would not have figure out myself that one could plug the cable the wrong way without even forcing it. Indeed on the Mac Book Pro one can not invert the the plugging.

François.

Hi guys

I have spent all day on this and the answer is much more simple having read a great blog.

What I want is Imac + apple mouse + apple keyboard to flip between imac and mac book pro in clamshell mode and vice versa

The solution is neat

Power off both the macbook pro and the imac

Have thunderbolt cable connected between the imac and macbook pro

Hold the T key down while booting up the macbook pro which will take it into thunderbolt disk mode

(You will see a lightening symbol on the screen) - once you have this you can shut in clamshell mode

Hold the OPTION key while booting up the imac - keep holding OPTION key until set of disks appear on screen

This will provide a choice of disks - select the macbook pro disk

This will now boot up the imac processor and memory, the macbook pro disk and the apple wireless mouse and keyboard will operate the macbook pro

To go back to Imac simpley shutdown and power up without OPTION button.

To go back to Macbook Pro shutdown and power up with OPTION button.

cheers

Awesome tip! I have just been trying out using my mac air (2012) in thunderbolt target disk mode via my imac (2012). Works very well - never thought it would!

I am not having any success conecting my iMac mid 2011 to my new Mac Mini server via thunderbolt. Both Macs are Thunderbolt equipped. When I press Command F2 the screen changes and I get a Log in window to type a password. Whe I try to type the password I am unable to because my Bluetooth Apple Keyboard is unavailable. What can I try?

have you probelm after tunderbolt update?

Thanks for the note about the reversal of the cable!

It was driving me crazy trying to figure out why target mode would not work even though everything seemed right. Seems like a pretty big design flaw to have a cable that can be inserted either way but will only work one way.

Wow, thank you for mentioning that the TB cable can be inserted backwards on the iMac! I had no idea that was even possible. I looked, and sure enough mine was reversed. I did notice it was a little hard to insert, but didn't think much of it.

Cheers!