I've tried to do this twice but still get a prompt warning me that the version I'm using will time out on 4/16/13 each time I load MC.
I'm using version 18.0.164 -- the latest I believe.
I've had the prompt "license successfully installed" at least twice. Still get the time out prompt.
I'm also getting emails asking me to purchase -- but I did purchase, that's how I got MC for Mac in the first place!