Is the path where Steam is installed on your computer. ex : “c:\program files (x86)\Steam”
%STEAMDIR% is en environment Variable that must be set before you run maya.
You can edit that path into the” config/mesa_config.bat” file, by replacing the path of the Environment variable that is named ” %STEAMDIR% ”
in version MESA 1.1 do not exists
with MESA 2.0 / 2.01 you must to restart maya to apply the environment variable modifications.