crwdns2934241:0crwdne2934241:0 Dan

crwdns2934249:0crwdne2934249:0:

Double check to make sure your ports are indeed Thunderbolt.

The older MacBook Pro's had mini DisplayPort which looks the same! The port needs to have a lightning bolt next to it. As an example, the 2009 & 2010 models have a DP port, both 2011 models have Thunderbolt.

crwdns2915684:0crwdne2915684:0:

open