Where apps hide your files

Finding OneNote's cache on a Mac

Updated 2026-10-28 · 6 min read

OneNote for Mac does not keep your notebooks as .one files you can pick up. Notebooks live in OneDrive or SharePoint, and the Mac keeps a private cache inside the app's container. Here is where, and what is safe to do with it.

Where the cache is

~/Library/Containers/com.microsoft.onenote.mac/Data/Library/Application Support/Microsoft User Data/OneNote

Answers on Microsoft's Q&A forum give this location for the OneNote cache and add that only OneNote can read it. On the Mac used for this guide OneNote is not installed and its leftover container has no Microsoft User Data folder, so the inner path comes from those answers. To see what yours contains:

ls ~/Library/Containers/com.microsoft.onenote.mac/Data/Library/Application\ Support

Open it with Go > Go to Folder (⇧⌘G). Finder may list the container by the app's name, such as Microsoft OneNote, rather than com.microsoft.onenote.mac, so look for either.

Office apps also share a group container, ~/Library/Group Containers/UBF8T346G9.Office. On the Mac used for this guide it holds shared items such as Licenses, MicrosoftRegistrationDB, User Content.localized and an Outlook folder. List yours:

ls ~/Library/Group\ Containers/UBF8T346G9.Office

Where the notebooks really are

OneNote for Mac syncs notebooks from OneDrive or SharePoint. The master copy is online, and the Mac holds a cache of the notebooks you have opened. There are no .one files in the cache folder to copy, and in practice the cache is unreadable outside OneNote.

If you hoped to find a notebook as a file, open OneDrive or onenote.com in a browser: that is where the notebook itself lives.

Notes that only exist in the cache

This matters before you touch anything. Changes you made while offline sit in the cache until they sync, and answers on Microsoft's forum say that once a notebook is gone from the app, the suggested way back to an older cache is a Time Machine copy of the container. Open OneNote, check that notebooks show no sync error, and let it finish syncing. Do not clear the cache while a sync is failing.

Getting content out the supported way

OneNote for Mac exports one page at a time: go to the page and choose File > Save as PDF, per Microsoft's help. The PDF is a snapshot that later edits do not update. For a full copy of a notebook, the online version in OneDrive is the dependable source.

Clearing the cache

Clearing the cache is the usual fix for notebooks that will not sync or show stale pages. The reset given in a Microsoft Q&A answer removes OneNote's whole container:

1. Confirm your notes are online (open the notebook at onenote.com).
2. Sign out, then quit all Office apps.
3. In Finder, press ⇧⌘G, go to ~/Library/Containers and move com.microsoft.onenote.mac to the Trash.
4. Restart the Mac, open OneNote and sign in. Notebooks download again.

Anything that had not synced goes with the container, which is why step 1 matters. Some troubleshooting threads also have you trash UBF8T346G9.Office; that affects every Office app, and an answer on Microsoft's forum warns it removes Outlook data. Back it up first and treat it as a last resort. Use the Trash rather than deleting outright, so you can put things back.

How big it gets

du -sh ~/Library/Containers/com.microsoft.onenote.mac

Size follows the notebooks you have opened and the images inside them, so a notebook with many scans and clippings will be large. Remember that size here is a cache, and clearing it re-downloads, which can take a while on a slow connection.

Backing up or moving to a new Mac

You do not need to move the cache. Install OneNote on the new Mac, sign in with the same Microsoft account, and open your notebooks; they download from OneDrive. Copying the container to another Mac is not a supported way to move notebooks.

Signing in and out

Because the cache belongs to your account, signing out of OneNote and back in is a gentler reset than touching folders, and it is worth trying first when a notebook shows stale content. Use the app's account settings rather than Finder for that. If a notebook still refuses to refresh, only then move to the container reset above.

Several Office apps, one account

OneNote, Word, Excel and PowerPoint share licensing and sign-in data through the UBF8T346G9 group containers, which is why a sign-in problem in one app can appear in all of them. If one Office app asks you to sign in repeatedly, that is a hint the shared data is the issue and not OneNote's own cache. Fixing it is a wider job than clearing a cache, and Microsoft's support pages walk through it.

Why search finds nothing

The cache lives inside an app container in ~/Library, which Spotlight and Finder searches leave out, and its files are internal data with no page titles in their names.

Finding it next time

Everywhere indexes file names inside app containers once it has Full Disk Access, so typing onenote.mac finds the container, and typing UBF8T346G9 lists the shared Office group containers. Press ⌘↵ to reveal one in Finder. It searches names only, so notebook and page titles stay out of reach.

Common questions

Where is the OneNote cache on a Mac?

Microsoft's community answers place it under ~/Library/Containers/com.microsoft.onenote.mac/Data/Library/Application Support/Microsoft User Data/OneNote. It is readable only by OneNote.

Where are OneNote notebooks stored on a Mac?

In OneDrive or SharePoint. The Mac app keeps a private cache of notebooks you have opened, not separate .one files.

How do I clear the OneNote cache on a Mac?

Check your notes are synced, sign out and quit all Office apps, move com.microsoft.onenote.mac from ~/Library/Containers to the Trash, then restart and sign in again.

Will clearing the OneNote cache delete my notes?

Not synced notes, which are online. Edits that failed to sync can exist only in the cache, so make sure nothing shows a sync error first.