How to reproduce:
1. Open Environment Variables window (Control Panel -> System and Security -> System -> Advanced system settings -> Environment Variables)
2. Create a PATHEXT User Environment Variable
3. Set the Variable value to %PATHEXT%;.RB;.RBW
4. Open Unity Hub
5. Create a new project or open an existing one
6. Create a new script

Expected result: Script is created and no errors are thrown in the Console
Actual result: Script is created and empty error is thrown in the Console

Reproducible with Unity versions: 2019.2.15f1

Reproducible with Unity Hub versions: 2.2.0, 2.2.1

Notes:
- The following error message is logged in the Editor.Log: Editor\Data\Tools\RoslynScripts\..\..\Tools\Roslyn\csc"' is not recognized as an internal or external command, operable program or batch file.