RiotGames/ridley — pull request #177 by KAllan357 (2013-06-14 19:42:40+00:00)
Title: use setx in conjunction with set

Set - sets a variable for the current session
Setx - sets a variable for the system

Using both should ensure that the path stays set.

http://batcheero.blogspot.com/2008/02/set-and-setx.html