How to display emails older than 12 months in Microsoft Outlook

The default number of months that are configured for your profile varies by the size of your hard disk. This is designed to help performance and save storage space on your PC. The web version of Outlook will always have all of your emails accessible regardless of their age.

If you have to change the number of selected months of email to synchronize with your cached mode, follow these steps:

Start Outlook.
On the File tab, click Account Settings, and then click Account Settings.
On the E-mail tab, double-click your Microsoft Exchange account.
In the Change Account dialog box, drag the Mail to keep offline slider to the desired number of months or to All to synchronize all email messages.
Click Next.
Click OK when you're prompted to restart Outlook to complete the configuration change.
Click Finish.
Restart Outlook.