How to Password Protect a OneNote Section to Secure Private Notes

Microsoft OneNote is an excellent tool for organising everything from meeting minutes to personal journals. However, if you share a notebook with your family, or if your IT department has access to your work computer, you likely have certain sections—such as personal financial details, passwords, or confidential HR notes—that you want to keep completely private.

Fortunately, OneNote allows you to apply military-grade AES-128 encryption to individual sections within your notebooks. This means you can share a notebook freely, but keep specific tabs completely locked down and inaccessible to anyone who does not know the exact password.

Applying a Password to a Section

It is important to understand that you can only password-protect an entire Section (the coloured tabs at the top or side of your screen), not individual pages or entire notebooks.

1. Open the Microsoft OneNote application on your computer.
2. Navigate to the notebook and locate the specific Section tab you want to secure.
3. Right-click on the section tab.
4. From the dropdown menu, select Password Protect this Section.
5. A new panel will open on the right side of your screen. Click the button labelled Set Password.
6. A small dialog box will appear. Type your desired password, then type it again to confirm.
7. Click OK.

Your section is now secured, but it remains unlocked for you while you are actively working in it. To lock it immediately, press Ctrl + Alt + L (or click the “Lock All” button in the right-hand panel).

Important Warnings About OneNote Passwords

Before you lock away your most important data, there are two critical warnings you must keep in mind regarding Microsoft’s encryption system.

1. There is no password recovery: If you forget the password you assigned to a section, Microsoft cannot recover it for you, and there is no “Forgot Password” link. The data within that section will be permanently inaccessible. It is highly recommended to store your OneNote password in a secure password manager.
2. Search is disabled: The global search function in OneNote cannot look inside locked sections. If you are searching for a specific word, you must manually unlock the secured section first before running the search, otherwise, the contents will be completely ignored.

Removing a Password

If you no longer need the security and want to make the section easily accessible again, you can remove the encryption entirely.

1. Right-click on the protected section tab and select Password Protect this Section.
2. In the right-hand panel, click the Remove Password button.
3. OneNote will ask you to enter the current password to prove you have the authority to remove it. Type the password and click OK.