It sounds like maybe you are using a firewall software that blocks the OpenModelica process from communicating with OMNotebook. If so, OMShell will give you the same kind of errors.

If you kill the process manually, the omc.exe process will still be alive in the background. You also need to shut that down if a tool crashes.

Okay!

I didn't think that the firewall could be the problem.
Now, it works correctly and I can begin my project after 2 days of incomprehension and despair!

Thank you for this efficent answer.

Actually, It doesn't work correctly. I still have a problem with the evaluation. I try to fix it with a complete reinstallation but no result.
In the shell, I have this error message:


But I found this file in the bin folder as we can see it:


(My firewall is desactivated now.)

So, do you have any idea of the reason of this problem?

Thanks a lot.

There is a major problem with mingw and using spaces in path names.
So installing in C:\Program Files\ will not work. It's too bad the installer won't detect this and scream. Maybe we should look for spaces in OPENMODELICAHOME and generate better error messages...