Grunt is not working for all Windows users. Some users are facing some issues, when I run npm install command; it prints a message as below.
E:\\Wor
Your logs indicate that the grunt command was created in your global directory. The errors also indicate that C:\Users\mc862634\AppData\Roaming\npm\ is not in your path.
You'll want to check your PATH and make sure that the \AppData\Roaming\npm location is added if it is missing.
The easiest way to check is to open a command prompt and type PATH.
See this other StackOverflow question as a reference: Grunt on Windows 8: 'grunt' is not recognized