There is a default work environment for MEP. You may want instead to customize your work environment to include MEP. Also, check that you have loaded the MEP library or else you will see the MEP tools and tool bar but they will be grayed out.
HTH
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"
