Not so fast there; this didn’t work for me!
After futzing around ends up I have a $ (dollar sign) in my password, and that is causing a problem!
Try setting your Mac to something with a $ followed by at least one other character – the utility doesn’t work then. For example, I used: $123.
I also tried my pw w/o a $ and also tried with the $ as the last character – both of these worked.
Looks like there is some problem with processing passwords with this utility?
BTW, I’m on a late 2013 Mac Pro w/Mac OS 10.11.5 installed, but only been using it new out of the box for about a month, so no “crufty” problems should be lurking having a machine for a long period of time . . .