Where apps hide your files

Outlook's storage on macOS

Updated 2026-07-31 · 4 min read

Outlook keeps everything in one profile folder, and its size surprises everyone who finds it.

The location

~/Library/Group Containers/UBF8T346G9.Office/Outlook/Outlook 15 Profiles/Main Profile/Data

Messages, attachments and the account database all live under that profile. (The "15" is historical and persists across versions.) All inside ~/Library, all invisible to Spotlight.

Attachments specifically

Attachments are stored within the message store rather than as one tidy folder of files. The supported way to get one is from Outlook itself: open the message → right-click the attachment → Save As, or drag it into a Finder window.

For bulk work, select multiple messages → drag attachments out, or use File → Save As on messages to export .eml files containing them.

Searching Outlook mail

Outlook's own search depends on its internal index, which has its own repair ritual when results go wrong: quit Outlook, then relaunch — recent versions rebuild automatically when the database is flagged. Persistent failures are usually fixed by removing and re-adding the account (mail redownloads from the server).

The size problem

The profile grows with every cached message:

du -sh ~/Library/Group\ Containers/UBF8T346G9.Office 2>/dev/null

Tens of gigabytes is normal for old accounts. Outlook → Settings → Accounts → adjust how much mail syncs locally to shrink it.

The takeaway that generalises

Mail clients — Outlook, Apple Mail, Thunderbird — all store attachments inside opaque stores under ~/Library. The reliable pattern: save anything you will need again into your own folders at the moment you receive it, because "it is in my email somewhere" is the slowest search there is.

Common questions

Where does Outlook for Mac store its data?

In the Office group container: ~/Library/Group Containers/UBF8T346G9.Office/Outlook/…, as one profile folder.

Why can Spotlight not find my Outlook attachments?

They live inside Outlook's database within ~/Library — excluded territory. Save attachments out to your own folders to make them searchable.