.ONETOC File

What is a .ONETOC file?

A .ONETOC file is a table of contents file used by older versions of Microsoft OneNote (2003 and earlier). It stores information about the structure of a OneNote notebook, including the order of sections and pages, as well as the properties of each section and page. The .ONETOC file is essential for the integrity of a OneNote notebook, and if it is deleted or corrupted, the notebook may not open or synchronize properly.

.ONETOC files are created and maintained by OneNote automatically, and users should not need to interact with them directly. However, there are a few situations where users may need to know about .ONETOC files, such as if they are trying to recover a lost or corrupted notebook from an older version of OneNote, or if they are trying to convert their notebook to a newer format.

Here are some additional things to know about .ONETOC files:

• .ONETOC files are binary files, which means that they cannot be opened or edited in a text editor.
• .ONETOC files are typically located in the same directory as the OneNote notebook files.
• .ONETOC files are created and updated whenever changes are made to the notebook.
• .ONETOC files are used by OneNote to synchronize notebooks across different devices and platforms.

Note: Newer versions of OneNote use the .ONETOC2 file format for tables of contents.

How to open a .ONETOC file?

To open a .ONETOC file, you can use either Microsoft OneNote 2003 or earlier, or a OneNote converter.

To open a .ONETOC file in OneNote 2003 or earlier:

1. Open OneNote.
2. Click the File menu.
3. Click Open.
4. Navigate to the .ONETOC file and click Open.

To open a .ONETOC file in a OneNote converter:

1. Download and install a OneNote converter, such as OneNote Converter or OneNote to Office.
2. Open the OneNote converter.
3. Click the Open button and navigate to the .ONETOC file.
4. Select the format that you want to convert the notebook to, such as PDF or XPS.
5. Click the Convert button.

Once the conversion is complete, you will be able to open the notebook in the format that you selected.

Note: It is not recommended to open a .ONETOC file in a text editor or other program. The .ONETOC file is a binary file, and opening it in a text editor or other program may corrupt it.

If you are having problems opening a .ONETOC file, you can try the following:

• Make sure that you are using the correct version of OneNote or OneNote converter.
• Try opening the .ONETOC file on a different device.
• Try converting the .ONETOC file to a different format.
• If you are still having problems, contact Microsoft support for assistance.

What is the difference between .ONETOC2 and .ONETOC files?

The main difference between .ONETOC2 and .ONETOC files is that .ONETOC2 files are used by newer versions of Microsoft OneNote (2010 and later), while .ONETOC files are used by older versions of OneNote (2003 and earlier).

.ONETOC2 files are also more efficient and reliable than .ONETOC files. They are smaller in size, and they are less likely to become corrupted.

Here is a table that summarizes the key differences between .ONETOC2 and .ONETOC files:

Feature	.ONETOC2 file	.ONETOC file
File format	Newer version	Older version
Compatibility	OneNote 2010 and later	OneNote 2003 and earlier
Efficiency	More efficient	Less efficient
Reliability	More reliable	Less reliable

If you are using an older version of OneNote, you can still open and edit notebooks that use the .ONETOC file format. However, it is recommended to convert your notebooks to the .ONETOC2 file format if you are planning to upgrade to a newer version of OneNote.

To convert a OneNote notebook from the .ONETOC file format to the .ONETOC2 file format, follow these steps:

1. Open OneNote.
2. Click the File tab.
3. Click Info.
4. Under Notebook Information, click Convert to OneNote 2010-2016.
5. Click Convert.

Once the conversion is complete, your notebook will be saved in the .ONETOC2 file format.

How to recover a deleted or corrupted .ONETOC file?

There are a few ways to recover a deleted or corrupted .ONETOC file.

1. Use the OneNote AutoRecovery feature. OneNote automatically saves a backup of your notebooks every few minutes. To recover a deleted or corrupted .ONETOC file using the OneNote AutoRecovery feature, follow these steps:

   1. Open OneNote.
   2. Click the File tab.
   3. Click Info.
   4. Under Notebook Information, click Open AutoRecovered Notebooks.

   OneNote will open a list of all of the AutoRecovery notebooks that are available. Select the notebook that contains the .ONETOC file that you want to recover and click Open.

2. Use a third-party data recovery program. There are a number of third-party data recovery programs that can be used to recover deleted or corrupted files. To recover a deleted or corrupted .ONETOC file using a third-party data recovery program, follow the instructions that are included with the program.

3. Contact Microsoft support. If you are unable to recover a deleted or corrupted .ONETOC file using either of the methods above, you can contact Microsoft support for assistance.

Here are some additional tips for recovering a deleted or corrupted .ONETOC file:

• If you have recently deleted the .ONETOC file, try to restore it from the Recycle Bin.
• If you have been using a cloud storage service to back up your OneNote notebooks, try to restore the .ONETOC file from the cloud storage service.
• If you are unable to recover the .ONETOC file, you can try to convert the notebook to a different format, such as PDF or XPS. This will allow you to open the notebook in a different program, such as Adobe Acrobat Reader or Microsoft Edge.

Note: It is important to note that there is no guarantee that you will be able to recover a deleted or corrupted .ONETOC file. The sooner you try to recover the file, the better your chances of success.