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You’re composing an important email and realize Outlook isn’t flagging a single typo. No red underlines. No spelling suggestions. Nothing. Outlook spell check has silently stopped working, and you have no idea when it happened.

This is one of the most common Outlook complaints, and it affects every version: classic Outlook desktop, the new Outlook for Windows, Outlook 365, and Outlook on the web. The good news is that the fix usually takes less than two minutes once you know where to look.

This guide covers every version of Outlook with exact menu paths and checkbox names. Find your version, follow the steps, and get spell check working again.

Why Outlook Spell Check Stops Working

Before jumping to fixes, it helps to understand what actually breaks. According to Microsoft’s official documentation on spell check in Office, the proofing engine relies on several settings all being configured correctly at the same time [1]. When any one of them is off, spell check goes silent without warning.

Outlook spell check fails for five specific reasons, and identifying yours will save you time.

Proofing language set incorrectly. Every email in Outlook has a proofing language attached to it. If that language gets set to one you don’t have proofing tools installed for, or gets switched to a language you didn’t intend, spell check goes silent. This is the number one cause, responsible for roughly 60% of cases. Microsoft acknowledged that proofing languages could change unexpectedly in new Outlook for Windows and deployed a service-side fix in December 2024 [2].

“Do not check spelling or grammar” is enabled. There’s a checkbox buried in the proofing language dialog that disables spell check entirely for the current document. It’s easy to enable by accident, and Outlook never warns you that it’s active. Once checked, spell check stops for that email and can persist across new messages.

Autocorrect and proofing disabled at the application level. Outlook has global proofing settings separate from the per-email language settings. If “Check spelling as you type” gets unchecked in Options, spell check stops across all emails without any visible indicator.

New Outlook moved the settings. Microsoft redesigned the settings interface in the new Outlook for Windows. If you recently switched from classic to new Outlook, your old settings didn’t carry over. The spell check options are in a completely different location, and they default to whatever Microsoft chose, not what you had configured before.

Add-in conflicts. Grammar extensions like Grammarly register as COM add-ins in Outlook and can override the native spell check engine. When two proofing tools compete for the same text, both can fail. This is especially common after Grammarly updates or when multiple grammar tools are installed simultaneously.

How To Fix Spell Check In Outlook

The fix depends on which version of Outlook you use. Here’s the step-by-step for each. Start with Fix 1 regardless of your version, since proofing language issues affect all of them.

Fix 1: Check Your Proofing Language

This single fix resolves about 60% of Outlook spell check failures. It works in every version of Outlook that has a ribbon. As Microsoft Support confirms, the proofing language must match the language you are writing in for spell check to function correctly [3].

1. Open a new email or reply to an existing one.
2. Click anywhere in the message body so your cursor is active in the text area.
3. Go to the Review tab in the ribbon.
4. Click Language, then select Set Proofing Language.
5. In the dialog that opens, select your language (e.g., English (United States)).
6. Uncheck the box labeled “Do not check spelling or grammar.” This is the critical step. If this box is checked, Outlook ignores every spelling error.
7. Click OK.

Type a deliberate misspelling to confirm spell check is active again. Note that this setting can reset after Office updates or when pasting content from external sources. If spell check stops working again after an update, come back to this dialog first.

Fix 2: Enable Spell Check in Classic Outlook Desktop

Classic Outlook (the version that’s been around for years, with the full File menu and ribbon) has two separate spell check settings. Both must be enabled for full coverage.

1. Click File in the top-left corner.
2. Select Options at the bottom of the left sidebar.
3. Click Mail in the left panel of the Options dialog.
4. Under the Compose messages section, check the box for “Always check spelling before sending.” This triggers a spell check every time you hit Send.
5. Now click the Spelling and Autocorrect button in the same section.
6. This opens the Proofing settings in the Editor Options dialog.
7. Under “When correcting spelling in Outlook,” make sure these boxes are checked:
   • Check spelling as you type
   • Mark grammar errors as you type
   • Frequently confused words
8. Click OK on both dialogs to save.

Key point: “Always check spelling before sending” (in Mail settings) and “Check spelling as you type” (in Proofing settings) are independent of each other. The first runs a final check when you click Send. The second shows red underlines as you type. Most people want both enabled.

Fix 3: Enable Spell Check in New Outlook for Windows

The new Outlook for Windows has a completely different settings structure. If you switched recently, your classic Outlook settings did not migrate.

1. Click the gear icon (Settings) in the top-right corner of the new Outlook window.
2. Select General from the left sidebar.
3. Click Privacy and Data, then open Privacy Settings.
4. Scroll to the bottom and under Connected Experiences, make sure “Turn on experiences that analyze your content” is switched on. Without this, Editor and spell check are disabled entirely.
5. Go back to Settings and select Mail from the left sidebar.
6. Click Compose and reply.
7. Scroll down to the spelling and grammar section and toggle on spell check and any grammar options you want active.
8. Close the settings panel. Changes save automatically.

Important: The new Outlook for Windows is built on web technologies, similar to Outlook on the web. Step 4 above is a frequently missed requirement that Microsoft introduced in recent builds. If the Editor button appears grayed out, the Connected Experiences privacy toggle is almost certainly the cause. The new Outlook does not have the same depth of proofing tools as classic Outlook.

Fix 4: Enable Spell Check in Outlook on the Web (OWA)

Outlook on the web has the most limited native spell check of all Outlook versions. Here’s how to make sure what’s available is actually turned on.

1. Open outlook.office.com in your browser.
2. Click the Settings gear in the top-right corner.
3. Select Mail from the sidebar.
4. Click Compose and reply.
5. Look for the spelling options and make sure they’re enabled.

Here’s what most people don’t realize: OWA primarily relies on your browser’s built-in spell check, not its own engine. That means your browser settings matter more than Outlook’s. In Chrome, go to Settings → Languages and make sure “Use spell check” is enabled for your language.

If you need grammar checking beyond basic spell check in OWA, a browser extension is the most reliable option. BeLikeNative adds professional-grade grammar and spell check directly inside Outlook on the web through Chrome, covering gaps that OWA’s native tools miss. Having similar issues in Google Docs? See our Google Docs grammar check guide for fixing spell check there too.

Also use Teams? Fix spell check in Microsoft Teams.

Fix 5: Disable Conflicting Add-ins

If you’ve verified all your settings are correct and spell check still isn’t working, an add-in is likely interfering. Grammar extensions are the most common culprit.

1. In classic Outlook, go to File → Options → Add-ins.
2. At the bottom of the dialog, make sure “COM Add-ins” is selected in the Manage dropdown, then click Go.
3. Uncheck all add-ins in the list. Click OK.
4. Restart Outlook completely (close and reopen, don’t just close the window).
5. Test spell check by typing a misspelling in a new email.
6. If spell check works now, re-enable add-ins one at a time, restarting between each, to identify which one causes the conflict.

Grammarly’s Outlook add-in is the most frequent offender. It hooks into the same proofing pipeline that native spell check uses, and conflicts are common after either Grammarly or Office updates. If Grammarly is causing issues, check if it’s currently experiencing an outage before spending time troubleshooting. If you’re looking for an alternative, BeLikeNative is a lighter option that works as a browser extension alongside Outlook without interfering with native spell check. You can also read our comparison of the best free Grammarly alternatives to see how the options stack up.

Outlook Spell Check Settings: Quick Reference Table

Microsoft has split Outlook into multiple versions, each with settings in different places. This table gives you the exact path for every current version.

Microsoft moves these settings periodically with feature updates. This table is current as of early 2026. If you’ve just installed a major update and can’t find the settings, check Microsoft’s official spell check documentation for your specific build number.

How To Turn On Spell Check Before Sending in Outlook

One of the most searched Outlook questions is how to make spell check run automatically before every email goes out. This is separate from the “check as you type” feature and acts as a final safety net.

In classic Outlook desktop:

1. Go to File → Options → Mail.
2. Under Compose messages, check the box for “Always check spelling before sending.”
3. Click OK.

Now every time you click Send, Outlook will run a spell check first. If it finds errors, it opens a dialog showing the mistakes and suggested corrections. You can fix them or click Send anyway.

In new Outlook and Outlook on the web: There’s no separate “check before sending” toggle. Spell check runs in real-time as you type, with errors underlined immediately. If you have the spelling options enabled in Settings → Mail → Compose and reply, you’re covered. There’s no additional step needed.

Keyboard shortcut: In any version of Outlook that supports it, press F7 to run a manual spell check on your current email. This works in classic Outlook and is useful as a quick check before sending even if automatic spell check is already enabled.

Outlook Spell Check In Wrong Language — How To Fix

A related and equally frustrating problem: spell check is working, but it’s flagging correct words because it’s checking in the wrong language. Every English word gets a red underline because Outlook thinks you’re writing in French or German.

How to fix it:

1. Open a new email or the email where spell check is using the wrong language.
2. Select all text in the message body (Ctrl+A).
3. Go to Review → Language → Set Proofing Language.
4. Select the correct language from the list.
5. If the wrong language keeps coming back, uncheck “Detect language automatically.” This feature tries to guess your language based on what you type, and it often guesses wrong, especially if you use technical terms, product names, or write short emails.
6. Click Set As Default if you want this language to apply to all future emails.
7. Click OK.

Microsoft confirmed in late 2024 that a bug was causing proofing languages to change unexpectedly in new Outlook for Windows. A service-side fix was deployed in December 2024 [2]. If you are still experiencing this issue after that date, use the manual steps above to lock your preferred language.

For multilingual users, constantly switching proofing languages is a real productivity drain. If you write emails in multiple languages throughout the day, BeLikeNative automatically detects your language and adjusts its grammar and spell checking without any manual switching. It supports over 80 languages and handles code-switching within the same email.

Prevent Spell Check Issues From Coming Back

Once you’ve fixed the immediate problem, take a few steps to avoid ending up back here.

Pin your proofing language. After setting the correct proofing language (Review → Language → Set Proofing Language), click “Set As Default” so it sticks across new emails. This prevents Office updates from resetting it.

Keep Outlook updated. Microsoft fixes spell check bugs in cumulative updates. Go to File → Office Account → Update Options → Update Now to make sure you’re on the latest build. Several spell check bugs in Outlook 365 were patched in late 2025 and early 2026.

Enable Connected Experiences in new Outlook. If you use the new Outlook for Windows, make sure Settings → General → Privacy and Data → Privacy Settings → Connected Experiences has “Turn on experiences that analyze your content” enabled. Without this, the Editor and spell check features are completely disabled.

Use a browser-based backup. Native spell check in Outlook depends on a chain of settings all being correct simultaneously. One checkbox in the wrong state breaks everything. A browser extension like BeLikeNative provides independent spell and grammar checking that works even when Outlook’s native tools fail. It’s especially useful if you switch between Outlook desktop and Outlook on the web, since it provides consistent proofing across both.

Using Microsoft Edge? Enable spell check in Edge for a backup option.

Set up your manual spell check shortcut. Press F7 in classic Outlook to run a manual spell check at any time. Make it a habit to hit F7 before sending important emails, even if automatic spell check is working. It catches things the real-time checker sometimes misses, like words that are spelled correctly but used in the wrong context.

Audit your add-ins quarterly. Extensions update themselves silently and can introduce new conflicts at any time. Every few months, check File → Options → Add-ins to see what’s running and disable anything you’re not actively using.

For Notion users, see our Notion grammar check guide.

FAQ

Why is my spell check not working in Outlook 365?

The most common cause is the proofing language being set incorrectly, or the “Do not check spelling or grammar” checkbox being accidentally enabled. Go to Review → Language → Set Proofing Language and make sure your language is selected and the “Do not check” box is unchecked. If that doesn’t fix it, check File → Options → Mail → Spelling and Autocorrect to verify that “Check spelling as you type” is enabled at the application level.

Where is spell check in the new Outlook?

In the new Outlook for Windows, spell check settings are under Settings (gear icon) → Mail → Compose and reply. This is different from classic Outlook where it’s under File → Options → Mail. The new Outlook also relies on Microsoft’s Editor proofing engine, which requires Connected Experiences to be enabled in your privacy settings [1].

Does Outlook web have built-in spell check?

Outlook on the web (OWA) has limited built-in spell check and primarily relies on your browser’s spell check feature. This means Chrome, Edge, or Firefox handles most of the spelling corrections, not Outlook itself. For more thorough grammar and spelling correction in OWA, a Chrome extension like BeLikeNative adds professional-grade proofing directly inside Outlook web.

How do I enable spell check before sending in Outlook?

In classic Outlook: File → Options → Mail → check “Always check spelling before sending.” This makes Outlook run a full spell check every time you click the Send button [3]. In new Outlook and Outlook on the web, spell check runs automatically in real-time if enabled in Settings → Mail → Compose and reply, so there’s no separate “before sending” option needed.

Can Grammarly cause Outlook spell check to stop working?

Yes. Grammarly and other grammar extensions can interfere with Outlook’s native spell check by overriding its proofing engine. This is one of the most common causes of spell check failures in Outlook desktop. Try disabling the Grammarly add-in temporarily (File → Options → Add-ins → COM Add-ins) to see if that resolves the issue. If it does, you’ll need to choose between Grammarly and native spell check, or switch to a lighter tool that doesn’t conflict with Outlook’s built-in proofing.

Why does Outlook spell check keep switching to the wrong language?

This is typically caused by the “Detect language automatically” feature, which guesses your language based on what you type and frequently guesses wrong. Go to Review → Language → Set Proofing Language, uncheck “Detect language automatically,” select your correct language, and click “Set As Default.” Microsoft also fixed a known bug in December 2024 that caused proofing languages to change unexpectedly in new Outlook [2].

Sources

1. Microsoft Support — Check spelling and grammar in Office
2. Microsoft Support — Microsoft Editor proofing or spellcheck languages change unexpectedly in new Outlook for Windows
3. Microsoft Support — How to spell check before sending emails in Outlook