Creo ModelCHECK > Configuring PTC Creo Modelcheck > Setting Up the Start Configuration File > About the Start Configuration File
  
About the Start Configuration File
The start configuration file, or start file, stores the initialization information for part mode, assembly mode, drawing mode and external files. Creo ModelCHECK uses the information while checking models. The start configuration file has the .mcs extension.
You can have several start configuration files and use more than one at a time. The condition file determines which start file to use each time you run Creo ModelCHECK.