I tried opening the Flutter doc file after installing it on Windows 8.1 Pro. I have only tried double-clicking (left mouse) on the file.
Solution 1: Rakitha Fernando
I tried opening the flutter_console.bat file by right-clicking and clicking Run as the administrator, it resolved the problem.
Solution 2: Marcel Hofgesang
I don't think it is supposed to run flutter doctor the way you are trying.
Usually you open the directoy of your flutter project in the terminal and execute
Please read the documentation for further information: https://docs.flutter.dev/get-started/install/windows#run-flutter-doctor