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View a ONETOC2 file online, free

A .ONETOC2 file is a Microsoft OneNote table of contents. Drop it in to inspect its real format, size and contents, free.

Drop your .ONETOC2 file here

Opens your .ONETOC2 file right here.

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Up to 50 MB · 160+ text and code extensions
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What you get for a .ONETOC2 file

We don't have a dedicated viewer for this format, so we identify and inspect it instead — honestly, only what can be read from the file.

01

Drop your .ONETOC2 file

Choose it or drag it in. It's read right here in your browser.

02

We identify it

We read the magic bytes to tell what the file really is, its MIME type, and whether the name matches the contents.

03

See the details

Any metadata we can extract (dimensions, EXIF/GPS, document author and dates), a hex view, plus readable text and strings found inside.

What is a .ONETOC2 file?

Plain text that programs, servers and people write every day.

A .ONETOC2 file is a Microsoft OneNote Table of Contents file categorized as a settings file. It contains data used to organize and track the structure of notebook sections and is typically opened with Microsoft OneNote or the Microsoft Office suite.

Programs that open .ONETOC2 files

Windows
Microsoft OneNote, Microsoft Office
macOS
Microsoft OneNote (macOS)
Android
Microsoft OneNote (Android)
iOS
Microsoft OneNote (iOS)
Web
OneNote Online (Microsoft 365)
.ONETOC2 format details
Full nameMicrosoft OneNote Table of Contents File
DeveloperMicrosoft Corporation
First released2010 (OneNote 2010 introduced .onetoc2; replaces legacy .onetoc)
CategoryText & Code
MIME typeapplication/msonenote
SignatureE4 52 5C 7B 8C D8 A7 4D AE B1 53 78 D0 29 96 D3 äR\{

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Frequently asked questions

Is my .ONETOC2 file uploaded anywhere?

No. The file is read and highlighted for you.

Why do some characters look wrong (é, ł)?

That usually means the file was saved in one encoding and opened in another. We detect UTF-8, UTF-16 and the Windows-1250/1252 code pages automatically and show which one was used.

Can it handle huge log files?

Yes, up to 50 MB. Only the lines on screen are drawn, so scrolling stays smooth. Syntax colours are switched off for files over 1.5 MB to keep things fast.

How do the log level filters work?

We find levels like ERROR, WARN, INFO and DEBUG on each line. Lines without a level, such as stack traces, stay with the entry above them, so filtering to errors keeps the full trace.

Can I edit the file?

This is a viewer. To change code, download it or copy it into your editor. Converting encodings and line endings is planned.

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