Using Target Display Mode

[gadgetgirl85]

I bought a thunderbolt cable and have plugged my rMBP into my iMac because I want to use the iMac as the primary display. I hit command F2 on the iMac and I can see the background of my rMBP on there but it won't let me control anything and doesn't show up all my windows that are on my rMBP. Am I doing something wrong?

 

[satcomer]

After you do the connections use System Preferences->Displays. To use Target Disk Mode.

 

[jg321]

You'll have to use the keyboard and mouse of the MBP, not the one of the iMac. From what you've described, it's the iMac one's you're trying to use?