Hi,
It is my understanding that you are trying to use ‘InitFcn’ callback from the model properties callback of the Simulink to run checks and give custom error messages. The ‘InitFcn’ callback should be used for declaring the variables in the workspace which are not defined and are needed at the time when you run the model. ‘InitFcn’ callback should not be used for checking the model or for commands that simulate the model. Try using ‘StopFcn’ callback for this task. The ‘StopFcn’ callback will execute when a simulation stops by either running to completion or is stopped by the user.
Go through these documentation links for further details
