If you guys got a problem with people asking this type of questions please hit "repport post" and let a more experienced person make that decision.
If there is a "million threads about this" why not be more helpful and give a link to some of this threads?
Use PC Suite for upgrading the phone!
If PC Suite doesn't detect the new update, choose the repair firmware (or something called like this) and it will unroot your phone, then update via ota.
You won't lose any data with this method.
Guys. Use Search!
Sent from from my LG-D855