Why Does the Mac Check Spelling as I Type?
macOS has a system-wide spell-checking engine that actively monitors your keystrokes in almost every application, from Apple Mail and Messages to Notes and third-party text editors. When it detects a misspelled word, it immediately underlines it with a jagged red line. If the “Autocorrect” feature is also on, it might forcefully change the word without asking.
If you type in multiple languages, use heavy technical jargon, or simply find the constant appearance of red squiggly lines distracting while you are trying to brainstorm or write a rough draft, you can disable this live spell-checking feature entirely.
How to Turn Off “Check Spelling While Typing”
You can adjust the system-wide spelling behavior directly from your Mac’s Keyboard settings.
- Click the Apple Logo in the top-left corner of your screen.
- Select System Settings… (or System Preferences on older versions).
- Scroll down the left-hand sidebar and click on Keyboard.
- Look for the section labelled “Text Input” and click the Edit… button next to “Input Sources.”
- A new window will appear. Ensure the All Input Sources tab is selected on the left.
- Look at the options on the right side. Find the dropdown menu labelled Spelling (it is usually set to “Automatic by Language”).
- Right below the dropdown, find the toggle or checkbox labelled Correct spelling automatically and turn it Off to stop aggressive autocorrect.
- To completely stop the red underlines as you type, you must also look for the setting specifically named Check spelling: (This may be in the app’s Edit menu if not in System Settings).
App-Specific Disabling
If you only want to disable the red lines in a specific app (like Pages or Mail), you don’t need to change system settings. Simply open the app, click Edit in the top menu bar, hover over Spelling and Grammar, and uncheck Check Spelling While Typing. The red squiggles will instantly vanish from your current document.