Set run directory to Z:
Native Launcher Version: 286
Operating System: Windows 7 Professional
Application Hash: 8f1d31dfea0301cfa2ca7aaedc34da8e9fa25b31
Application Data directory: C:\Users\user\AppData\Roaming
Executable Path: Minecraft.exe
App Directory dir: Z:
Start dir: Z:
Launcher dir: Z:/game
TmpDir dir: Z:/game
Java Launcher hash: f9d59d273807f7b98f8e32d327ac7964481246d4
Java Version: 1.8.0_25
x64: 0
Specified proxy is used
A Proxy bypass list is used 
LauncherConfiguration from: https://launchermeta.mojang.com/mc/launcher.json
Failed to download config file
Failed to download manifest
runJavaLauncher
Started application ./runtime/jre-x32/1.8.0_25/bin/java.exe -cp Z:/game/launcher.jar net.minecraft.launcher.Main --nativeLauncherVersion 286
Application still running, assuming all's fine.