How to Fix Autocorrect on Mac (Step-by-Step)

Most Mac autocorrect problems have a quick fix in System Settings. If autocorrect keeps changing a word you want left alone, add a text replacement. If it is not working at all, check that "Correct spelling automatically" is toggled on. If it is missing from certain apps entirely, that is a deeper macOS limitation - one that requires a different approach to solve.

Problem 1: Autocorrect keeps changing a word you don't want changed

This is the most common complaint. You type a name, a product term, or a technical word - and macOS substitutes something else. The fix is to teach macOS to treat that word as intentional.

How to fix it: Open System Settings, then go to Keyboard, then Text Input, then Edit. In the Text Replacements panel, click the + button. In the "Replace" field, type the word exactly as you type it. In the "With" field, type the same word again. This creates a replacement rule that returns the word unchanged, overriding any automatic substitution macOS would otherwise apply.

If you want to stop all automatic substitution system-wide, you can also toggle off "Correct spelling automatically" in the same panel - though this removes autocorrect entirely rather than just excluding specific words.

Problem 2: Autocorrect isn't working at all

If nothing is being corrected as you type, the feature may have been switched off at some point - intentionally or during a macOS update.

How to fix it: Go to System Settings, then Keyboard, then Text Input, then Edit. Look for the toggle labelled "Correct spelling automatically" and make sure it is on. Also check that the correct input language is listed in your keyboard sources - autocorrect only functions for languages with an active dictionary installed on your Mac.

According to Apple's own documentation, autocorrect is enabled by default on macOS but can be reset or disabled by third-party keyboard utilities and system migration processes.

Problem 3: Autocorrect only works in some apps, not others

This is the most frustrating problem because the fix is not obvious from System Settings. You have autocorrect enabled, it works in Safari and Notes, but nothing happens in Slack, VS Code, or your project management tool.

Root cause: macOS autocorrect works through a framework called NSSpellChecker. For an app to receive autocorrect, it must explicitly call into this API. Most native Apple apps do. But a large number of popular third-party apps - Slack's desktop app, VS Code, Notion's desktop app, and virtually all Electron-based apps - do not integrate with NSSpellChecker. From macOS's perspective, those apps simply never ask for corrections.

Studies of enterprise Mac environments find that knowledge workers spend over 60% of their typing time in third-party apps rather than Apple's own tools - which means the default autocorrect system misses the majority of daily writing for most users.

The reliable fix: Charm solves this by taking a fundamentally different technical approach. Instead of relying on NSSpellChecker, Charm uses macOS's Accessibility API to monitor and correct text across every app simultaneously. It does not matter whether the app supports spell-checking natively - Charm operates at a layer that covers everything. You get corrections in Slack, VS Code, Terminal, Obsidian, and every other text field on your Mac.

Problem 4: Autocorrect is changing technical terms incorrectly

Developers, writers, and anyone who works with domain-specific vocabulary will run into this. macOS does not know what "useState", "kubectl", or your company's product names mean - so it substitutes something phonetically similar.

How to fix it: Add the terms to your personal dictionary. In System Settings, go to Keyboard, then Text Input, then Edit. Click the + button next to "User Dictionary" and type the term. Once a word is in your dictionary, macOS will treat it as valid and stop correcting it.

A faster method: when you see a red underline under a word in any supported text editor, right-click it and choose "Learn Spelling." The word is added to your user dictionary immediately without opening any settings panel.

Note that your user dictionary only applies in apps that use NSSpellChecker - so for apps like VS Code, this approach still will not help. See how Charm compares to macOS autocorrect for a full breakdown of this limitation.

Problem 5: Red squiggles everywhere but no autocorrection

Red underlines and autocorrect are separate features in macOS, and it is possible to have one without the other. Red squiggles indicate spell-check is active and flagging words - but that does not mean corrections are being applied automatically.

How to fix it: In System Settings, go to Keyboard, then Text Input, then Edit. You will see two separate toggles: "Check spelling while typing" (the squiggles) and "Correct spelling automatically" (the actual substitutions). If only the first is on, you will get red highlights but no automatic corrections. Turn on the second toggle to enable autocorrect.

If you prefer to remove the red squiggles entirely and just have silent automatic corrections, you can turn off "Check spelling while typing" while leaving "Correct spelling automatically" on. Charm takes this approach by default - it corrects as you type with no visual highlighting, so errors are fixed without drawing attention to them on shared screens.

The underlying fix for persistent autocorrect problems

If you have worked through all of the above and autocorrect is still unreliable, the root cause is usually macOS's architecture rather than a misconfigured setting. The built-in system was designed for Apple's own apps and relies on app developers to opt in - which many do not.

Charm takes a different technical approach. It uses the Accessibility API to intercept and correct text before it is submitted to any app, regardless of whether that app supports NSSpellChecker. This means:

• Corrections work in every app on your Mac - Slack, VS Code, Notion, Terminal, anything
• No red squiggles - corrections happen silently as you type
• All processing happens on-device - your text never leaves your Mac
• Grammar correction (Polish) and word prediction (Oracle) are included alongside spelling (Spells)
• One-time $9.99 purchase - no subscription

For users who are frequently frustrated with autocorrect gaps or app-specific failures, Charm is a more complete solution than adjusting System Settings. See the complete guide to autocorrect on Mac for a deeper look at how macOS spell-checking works and where it falls short.

Frequently asked questions

Why does Mac autocorrect keep changing a word I type correctly?

macOS treats the word as a misspelling and substitutes its closest match. To stop it, open System Settings, then Keyboard, then Text Input, then Edit, and add a Text Replacement where both the Replace and With fields contain the exact word. This tells macOS to leave it unchanged.

Why is Mac autocorrect not working at all?

Autocorrect may have been disabled. Go to System Settings, then Keyboard, then Text Input, then Edit and make sure "Correct spelling automatically" is toggled on. Also verify that the correct input language is selected for your keyboard.

Why does Mac autocorrect only work in some apps and not others?

macOS autocorrect relies on the NSSpellChecker API, which apps must explicitly support. Many third-party apps including Slack desktop, VS Code, and most Electron apps do not use this API. Charm bypasses this by using the Accessibility API instead, covering every app system-wide.

How do I stop Mac autocorrect from changing technical terms?

Add your technical terms to your personal dictionary. Go to System Settings, then Keyboard, then Text Input, then Edit and click the + button next to User Dictionary. Alternatively, right-click any red-underlined word in a supported app and choose "Learn Spelling."

What is the difference between red squiggles and autocorrect on Mac?

Red squiggles are spell-check highlighting - they mark a suspected error but do not fix it. Autocorrect automatically replaces the misspelled word as you type. Both features are controlled separately in Keyboard settings. You can have squiggles without autocorrect, or autocorrect without squiggles.