How do I protect a model?

Every time I try to protect a model or a referenced model, I get the following error that "an" error occurred while Building the model. I used the Matlab help "Create a Protected Model" and also the YouTube Video "Protecting Intellectual Property in Subsystems". The error is:

IC:/PROGRA~1/MATLAB/R2017b\sys\lcc64\lcc64\include64 -I../../../slprj/sim/_sharedutils cpp: Can't open input file 2 gmake: * [../../../Subsystem_msp.mexw64] Error 1 ### Build procedure for model: 'Subsystem' aborted due to an error. Error(s) encountered while building "Subsystem"

Has someone had that error and can help me protect my model or Subsystem (referenced model)? I would really appreciate it. Thanks.