Mech.htm - Displaying of this file indicates your file was created with Imagineer Technical 2.0 or Imagination Engineer 2.0.

Mechanical (ANSI).igr Template
<application.path>\..\symbols\Mechanical\Mechanical (ANSI)
 
Mechanical (ISO).igr Template
<application.path>\..\symbols\Mechanical\Mechanical (ISO)

Copy and paste one of the above locations into the browser address path under File>Properties Browser tab and this will point you to the latest symbol content for SmartSketch Version 3.0.