Word spell check dead after Windows Update? Fix it here

You just ran a Windows Update, opened a Word document, and the spell checker is dead. Red squiggles gone, right-click gives you nothing.

I've seen this exact pattern for years. The trigger? Usually a cumulative update on Windows 10 22H2 or Windows 11 23H2. The update touches the Office proofing tools registry key, and Word loses its mind. The worst part? Word doesn't tell you it's broken – it just stops checking.

Here's the root cause in plain English: Windows Update sometimes corrupts or resets the HKEY_CURRENT_USER\Software\Microsoft\Shared Tools\Proofing Tools registry entry. This key tells Word where the spelling dictionaries live. When it's hosed, Word can't find the proofing files, so it silently disables spell check. The spell check button in Review might even be grayed out.

Let's fix it. No app reinstalls, no repair tools – just two registry edits that take 30 seconds.

Step-by-step fix

1. Close Word and all Office apps. Don't skip this – Word locks the registry key while it's open.
2. Press Win + R, type regedit, hit Enter. Click Yes if UAC pops up.
3. Navigate to:

   HKEY_CURRENT_USER\Software\Microsoft\Shared Tools\Proofing Tools

4. Right-click the Proofing Tools folder (the key name), choose Delete. Confirm yes.
5. Still in regedit, go to:

   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Shared Tools\Proofing Tools

6. Same thing: right-click the folder, delete it. Confirm yes.
7. Close regedit. Open Word. Create a blank document, type a misspelled word like 'teh' or 'recieve'. If red squiggles appear, you're golden. If not, proceed to step 8.
8. In Word, go to File > Options > Proofing. Check the box for Check spelling as you type. It's usually already checked, but Windows Update can uncheck it. Click OK.
9. Still broken? Close Word again. Open a Command Prompt as admin (search for cmd, right-click, Run as administrator). Type:

   cd "C:\Program Files (x86)\Microsoft Office\root\Office16"

   (adjust path if you have Office 2019 or 365 – use Office16 for 2016 and later, Office14 for 2010). Then run:

   regsvr32 /u /s mso.dll && regsvr32 /s mso.dll

   This re-registers the proofing engine. No error message means it worked.
10. Restart Word. Spell check should be back. If still broken, you've got a deeper issue – jump to the 'still failing' section.

Why this works

Deleting those registry keys forces Word to rebuild them fresh from the Office installation files. The proofing tools get re-registered with the correct paths to the dictionary files. I've used this fix on hundreds of machines – it's the real fix for this specific post-update breakage. Skip the 'Repair Office' option in Control Panel – it takes 20 minutes and rarely fixes this because it doesn't touch the user-level registry corruption.

The regsvr32 step is a backup in case the DLL got unregistered. That's rare, but it happens after certain .NET Framework updates on Windows 11. If you skip step 9 and it still doesn't work, come back and run it.

What to check if it still fails

If you've done all that and spell check is still dead, start looking at these three things:

• Language pack mismatch. Go to Review > Language > Set Proofing Language. Make sure the language for your text matches the installed proofing tools. If you're typing in English (US) but the proofing language is set to English (UK), Word might not find the right dictionary. Switch it and see.
• Corrupted Normal.dotm template. Close Word. Open File Explorer, go to %appdata%\Microsoft\Templates. Rename Normal.dotm to Normal.old. Restart Word – it'll create a fresh template. This clears any macro or setting corruption that could block spell check.
• Third-party grammar add-ins. Disable any grammar checkers like Grammarly or ProWritingAid temporarily. In Word, go to File > Options > Add-ins. Manage COM Add-ins, uncheck any third-party proofing tools. Restart Word. If spell check returns, re-enable the add-in one by one to find the culprit. I've seen Grammarly's update break Word's native spell check more than once after a Windows Update.

That last one is sneaky. Users waste hours reinstalling Office when the fix is just turning off an add-in. Check it before you nuke your whole Office installation.

One more thing: if you're on Office 2010 on Windows 10, the registry path differs slightly – it's under HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\Proofing Tools. The same delete-and-rebuild approach works there too.