E-mails Over 1 Year Old Don't Show Up in Outlook
Problem Description
You may see this issue if you've just installed Outlook with the default settings, after upgrading from an older version like Outlook 2013 to the most recent version of Outlook 2016, or after applying Office updates.
The problem occurs because a default setting for the account limits mail kept locally on the PC to 12 months.
How to Fix This Issue
You can go to Outlook > Backstage (File) tab > Account Settings > Account Settings > click an account > Change button to find the slider that lets you adjust the setting from 12 months to All.
Note that you'll have to restart Outlook before the new setting will take full effect and it may take quite a while for Outlook to download all your messages.