Managing personal Outlook.com account settings, security, and privacy
As the Outlook sign in page is changed, I recommend you to try adding the Email address manually twice or thrice and check. The auto completion of Emails address might appear again.
Hi Syed,
Thanks for the suggestion. I've tried entering one of my addresses manually eight times. Still no sign of autocomplete reappearing.
I've mentioned this to a couple of friends who use Outlook.com. They also can't get autocomplete to appear.
It looks as though the problem is affecting everyone, and that something needs fixing on that sign-in page.