I've recently installed the "Simulink Support Package for Arduino Hardware", and tried to do the "getting started" basic model with the led blinking. 
But when i try to deploy the model on my board, i get this error :
 === Build (Elapsed: 4 sec) ===
    ### Starting build procedure for: first_step
    ### Generating code and artifacts to 'Model specific' folder structure
    ### Generating code into build folder: C:\Users\33687\Desktop\1-ESTACA\Matlab_test\first_step_ert_rtw
    ### Invoking Target Language Compiler on first_step.rtw
    ### Using System Target File: C:\Program Files\MATLAB\R2020b\rtw\c\ert\ert.tlc
    ### Loading TLC function libraries
    ### Initial pass through model to cache user defined code
    .
    ### Caching model source code
        ### Writing header file first_step_types.h
        ### Writing header file first_step.h
        ### Writing header file first_step_private.h
        ### Writing header file rtwtypes.h
        ### Writing header file multiword_types.h
        ### Writing source file first_step.c
    .
        ### Writing header file rtmodel.h
        ### Writing source file first_step_data.c
        ### Writing source file ert_main.c
    Error: File: C:\Program Files\MATLAB\R2020b\rtw\c\tlc\lib\utillib.tlc Line: 4412 Column: 19
    Unable to open output file C:\Users\33687\Desktop\1-ESTACA\Matlab_test\first_step_ert_rtw\modelsources.txt [ofstream::open operation failed]
    Main program:
    ==> [00] C:\Program Files\MATLAB\R2020b\rtw\c\tlc\lib\utillib.tlc:SLibCreateBuildSourcesTxtFile(4412)
        [01] C:\Program Files\MATLAB\R2020b\rtw\c\tlc\mw\formatwide.tlc:<NONE>(595)
    ### TLC code generation complete.
    ### Build procedure for first_step aborted due to an error.
    Top model targets built:
    
    Model       Action  Rebuild Reason                                    
    ======================================================================
    first_step  Failed  Code generation information file does not exist.  
    
    0 of 1 models built (0 models already up to date)
    Build duration: 0h 0m 4.267s
    Error:Error: Errors occurred - aborting
If anyone got the same problem and resolved it i'll be really grateful !