outlook - when sending email, the auto fill no longer works

[Marilyn Kneller-Rimsky]

In Outlook, I rely on the auto fill when typing an email address. usually, the name fills in after typing one or two letters. Since upgrading to windows 10, this feature no longer works. Although the list of correct email addresses appears, when I click on it, it no longer fills in the name and I have to completely retype the email address.

 

[Trouble]

Hello and welcome to the forum.
Can you advise.... when you say "Outlook" are we talking about the new Universal "Mail" app in Windows 10 or are we talking about Microsoft Office "Outlook" or perhaps outlook.com webmail?
IF the "Mail" app have you configured your account in the mail app and is it a Microsoft account or have you associated a different email account with the app.
The Mail, Calendar and People apps are all interlinked. Have you checked your "People" app and does it contain your list of contacts?
Have you tried resetting the cache
run wsreset.exe from the run command
OR
Have you tried running the troubleshooter
Control Panel\All Control Panel Items\Troubleshooting\ -> Left Column -> View All -> Windows Store Apps