Where are my OneNote files stored?

Nearly every OneNote recovery starts with the same step, and it is not a tool. It is a search. Before anyone can open a file for you, you have to establish which files exist. Surprisingly often the search itself solves the problem, because the automatic backup nobody knew about turns out to hold the notes.

Windows: local notebooks

A notebook stored on your own drive is a folder, not a file. The default location is under your Documents:

• C:\Users\<your account>\Documents\OneNote Notebooks\<Notebook name>\

Inside that folder you will find one .one file per section — those hold your pages and note text — and a table-of-contents file, usually Open Notebook.onetoc2, which records only the section order. If you are unsure which of those is worth rescuing, our guide to the OneNote file formats spells out what each contains.

Notebooks are frequently not in the default place, because people created them on a network share, an external drive, or a folder of their own choosing. Do not assume; search.

Windows: the automatic backup folder

This is the single most valuable folder in this article, and the one most people have never opened. The OneNote desktop app takes its own periodic backups of every section, entirely separately from any cloud sync.

• Current installs: C:\Users\<your account>\AppData\Local\Microsoft\OneNote\16.0\Backup\
• Older installs: the same path with 15.0, 14.0 or 12.0 in place of 16.0
• Windows Vista era: C:\Users\<name>\AppData\Microsoft\OneNote\12.0\Backup\
• Windows XP era: C:\Documents and Settings\<name>\Local Settings\Application Data\Microsoft\OneNote\Backup\

Inside are subfolders per notebook, containing ordinary .one files. They open the same way any section does.

AppData is hidden by default. In File Explorer, turn on Hidden items under the View menu, or paste %LOCALAPPDATA%\Microsoft\OneNote straight into the address bar and press Enter.

The backup location is configurable, so if it is empty, check where it was pointed: in OneNote, File › Options › Save & Backup shows the current backup folder. If someone redirected it years ago to a drive letter that no longer exists, that is worth knowing before you conclude there are no backups.

Windows: cloud notebooks and the local cache

If a notebook lives in OneDrive or SharePoint, the authoritative copy is in the cloud. Look under OneDrive › Documents › OneNote Notebooks, either in the synced folder on your PC or in the browser.

Two things to try there before anything else:

• Version history. OneDrive and SharePoint keep previous versions of files. An earlier, healthy copy of a section may be one right-click away.
• The Notebook Recycle Bin. Deleted pages and sections are retained there, and Microsoft's documentation puts the window at 60 days.

Separately, OneNote keeps a working cache on the local disk so it can function offline. The cache is not a folder of loose .one section files; it is internal working storage in its own layout. Copying cache files somewhere and hoping to open them as sections generally does not work. That distinction matters most for notes made in the app that shipped with Windows 10 — see what to do after that app retired.

Mac: a different picture

OneNote for Mac is documented as working with notebooks hosted on OneDrive, OneDrive for Business or a SharePoint library, rather than with locally stored notebooks the way the Windows desktop app can. Its working data lives in the app's container:

• ~/Library/Group Containers/UBF8T346G9.onenote/

Treat that, again, as internal working storage rather than a tidy shelf of section files. If you have loose .one files on a Mac — copied off an old Windows machine, say — they are just files sitting wherever you put them, and getting a Mac OneNote to accept them is its own subject: opening a local .one file on a Mac.

Sweeping the whole drive

When you do not know where to look, look everywhere. All of these are read-only searches and none of them changes a thing.

Windows

In File Explorer, select This PC and search for *.one. It is slow but thorough. From a command prompt, this is usually faster and gives you a list you can keep:

• dir C:\*.one /s /b > %USERPROFILE%\Desktop\one-files.txt

Repeat for *.onetoc2, *.onepkg and *.onebak. Include any external or network drives.

Mac

In Terminal:

• mdfind -name .one — quick, uses the Spotlight index
• find ~ -name "*.one" -print — slower, but does not depend on the index

What to do with the list

Sort it by size and by date. The largest files are usually the sections with the most content. The newest copy of a duplicated section name is usually the one you want, though a backup copy from before a problem started can be the better one — which is why you keep both.

A note on checksums, for anyone archiving properly

If these notes matter enough to keep for years, record a checksum for each original file at the moment you copy it. On Windows, certutil -hashfile <file> SHA256; on Mac, shasum -a 256 <file>. Save the output to a text file next to your copies.

That gives you two things. First, a record that lets you confirm later that the archived copy is byte-identical to the original. Second, a way to check that nothing you ran altered the source — you re-run the checksum afterwards and compare. This is the same principle we build into our own tools: a recovery tool should be able to demonstrate that it left your file alone, not merely assert it.

If you find the files but nothing will open them

Finding is the first half. If a section will not open, work through how to open a .one file without OneNote, which puts the free routes first, and the “older version of OneNote” message if that is what you are seeing.

For the case where none of that lands — an orphaned section, no working OneNote available, and what you need is the typed text — OneNote Rescue reads your own .one files locally and recovers page titles and note text to plain text, a readable HTML notebook and a JSON report. It is a small desktop app for Windows and Mac, and it copies your source to a temporary location and reads only the copy, so the original's bytes and timestamp are untouched.