npm – EPERM: operation not permitted on Windows

Running this command was my mistake.

npm config set prefix /usr/local

Path /usr/local is not for windows. This command changed the prefix variable at 'C:\Program Files (x86)\Git\local'

To access and make a change to this directory I need to run my cmd as administrator.

So I did:

1. Run cmd as administrator
2. Run npm config edit (You will get notepad editor)
3. Change prefix variable to C:\Users\<User Name>\AppData\Roaming\npm

Then npm start works in a normal console.