Office for Mac Issues

How to Stop OneNote from Changing Proofing Language on Mac

Maira Mehtab Sep 22, 2026 869 views

Question details

The user needs to prevent OneNote for Mac from automatically switching the proofing language (e.g., to German) when inserting pictures, formulas, or adding new pages.

Product: Microsoft OneNote
Device & OS: Mac
Scenario: Editing notes, adding new pages, inserting pictures, or typing formulas in OneNote for Mac.
Observed behavior: The proofing language automatically changes to an unwanted language like German, resulting in incorrect spell-check highlights, regardless of Mac system language settings.

Before you start

Ensure your Mac system keyboard and language settings are set to your preferred default language, as OneNote heavily relies on the currently active keyboard layout.

Solution 1Recommended

Manually Set the Proofing Language for Affected Text

Since Mac region and system settings alone do not entirely control page-level proofing, manually setting the language for the specific text block or page is the most direct fix.

OneNote for Mac occasionally attempts to auto-detect language based on inserted objects or background OCR, which can cause erratic proofing behavior. Overriding this manually will restore your intended spell-check settings.

Select the affected text

Click and drag to highlight the specific text, or press Cmd + A on your keyboard to select all content on the affected OneNote page.

Open the Tools menu

Navigate to the top menu bar on your Mac, click on 'Tools', and select 'Set Proofing Language' from the drop-down list.

Choose your preferred language

Select 'English' (or your desired language) from the dialog box and apply it to remove the incorrect spell-check underlines.

System Settings Limitations: Mac region and system language settings alone may not control page-level proofing in OneNote. This is a known behavior where inserted pictures or formulas disrupt the default dictionary.

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Frequently Asked Questions

Why does OneNote change the language when I insert a picture?

OneNote sometimes attempts to auto-detect languages based on optical character recognition (OCR) from the image. If it misinterprets the text in the picture, it may incorrectly switch the text box's proofing language to German or another language.

Does changing my Mac system language fix the OneNote proofing language?

Not always. While OneNote uses system preferences and active keyboard layouts as a baseline, page-level or text-block-level proofing languages can be overridden internally by the app when interacting with formulas or images.

Can I set a permanent default proofing language in OneNote for Mac?

Currently, OneNote for Mac lacks a single global setting to strictly enforce a default language across all notebooks permanently. It largely depends on your active Mac keyboard input source when creating the text, and occasional manual corrections are necessary.

How do I stop spell check completely for a specific word?

You can right-click the flagged word and select 'Ignore' or 'Add to Dictionary'. This ensures that the specific word will no longer trigger the red squiggly line in your current proofing dictionary.

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