Outlook Cache

Turn Cached Exchange Mode on or off

Click File > Account Settings > Account Settings.

Account Settings in the Backstage view

Click the Exchange or Microsoft 365, and then click Change.

Change command in the Account Settings dialog box

Under Offline Settings, check Use Cached Exchange Mode.

Use Cached Exchange Mode check box in the Change Account dialog box

(If you're a Microsoft 365 subscriber with semi-annual updates, under Offline Settings, check Use Cached Exchange Mode to download email to an Outlook data file.

Account setup dialog, Exchange Account Settings page.

4. Exit, and then restart Outlook.

If you want to turn off Cached Exchange Mode, repeat the steps, but clear Use Cached Exchange Mode.