I have a Nokia 640LTE and recently upgraded to Windows10 from 8.1. I then downloaded update 10586.318 and updates to standard apps. Then I set up outlook followed by my 2 Gmail accounts. My telephone contacts are there but outlook is missing many of my Gmail addresses. The sync from outlook to Gmail is faulty. I can receive a Gmail email via outlook and reply via outlook - no problem. But when I try and compose an email in outlook to be sent by one if my Gmail accounts, outlook cannot find the address. This is serious because I only got this phone to do email. Now I do my email by going to the Gmail site but that is not ideal because I have to look through both independently to find addresses. Outlook, when it was working with 8.1, was great.