Need help going back to Stock from GPE Lollipop topic

I relocked my bootloader. Turned S- ON and ran the correct RUU.exe file that I downloaded straight from HTC's website and I always get stuck during the update process(technically a downgrade I suppose) The RUU.exe always comes back with error 155 UNKNOWN ERROR. Not sure what I'm doing wrong. I ran ADB and checked before I ran the RUU that my PC does in fact recognize it( both while on my homescreen and FASTBOOT mode). Please I need help!