Read Your Outlook Email During an Outage: Cached Mode and Offline Mail

A local copy of your mailbox lets you keep reading and searching email when Microsoft has an outage. Here is how to make sure it is on.

1. Classic Outlook for Windows

Open the account settings.

File > Account Settings > Account Settings

2. Turn on Cached Exchange Mode

Select your account, click Change, and check Use Cached Exchange Mode. Restart Outlook if you changed it.

[x] Use Cached Exchange Mode

3. New Outlook

Turn on offline mail and choose how many days to keep.

Settings > General > Offline

4. What works during an outage

Reading and searching mail that already downloaded, plus writing drafts.

5. What doesn't

New mail can't arrive and sent mail waits in the Outbox until Microsoft is back.

Sources

Microsoft Outlook settings; ABC News, Al Jazeera, Fox Business, November 12-13, 2026.

FAQ

Does this use a lot of disk space?

It stores a copy of your mailbox. Limit it to the last few months if space is tight.

Does it help on my phone?

The Outlook phone app keeps recent mail on the device, so recent messages are often still readable.