1. Chkdsk needs to be 'run as administrator'. It complains about me not being authorised if I'm not. You can't change that behaviour, but that's not necessary either. All you have to do is to run the command processor as administrator and it will work fine.

2. In a command prompt window I can run cmd. It's c:\windows\system32\cmd.exe and that folder is in my path. So it's not clear why the mvn -version gives this error message. Seems a maven issue to me, not a Windows issue.