LanguageTool Not Working? Common Errors & Fixes

If the extension stopped underlining errors and asks you to upgrade, your 14-day Premium trial has ended: the extension is now Premium-only. Subscribe, connect it to a free self-hosted server, or use the free website editor.

Usually a Google Docs change broke the add-on (fixes ship within days), another writing add-on conflicts, or your browser extension is out of date. Update the extension, reload, disable other grammar add-ons, or use the Google Docs add-on from the Workspace Marketplace.

The Word add-in often breaks after updates: corrections don't apply, the panel is blank or suggestions point at the wrong line. Install all Windows and Office updates, switch to Print Layout on Mac, and reinstall the add-in.

Auto-detection fails on short texts and mixed-language documents. Limit LanguageTool to the languages you actually write in, and set the language manually for short or mixed texts.

Extension version 10.0.9 and later caused severe RAM spikes and crashes for many Firefox users in 2026. Roll back to version 9.0.1 and turn off automatic updates, or disable the extension on heavy pages.

LanguageTool often doesn't work in Overleaf's new Code Editor. Switch to the Visual Editor, make sure Overleaf isn't disabled in the extension, and try Chrome or Edge if you are on Firefox or Safari.

A bug has disabled the Chrome extension for some users; re-enable it at chrome://extensions and reload your tabs. Also check you are logged in to Premium, since the extension no longer checks on free accounts.

The free plan checks only 2,000 characters per text field; Premium raises the limit to 150,000. Split long text into chunks or upgrade.

Run the open-source LanguageTool server with Java on your computer and point the browser extension to 'Local server' in its experimental settings. This keeps the extension working without Premium, minus synonyms and Premium AI features.

Cancel on the website in your account settings under My account > Cancel subscription before the renewal date. App Store subscriptions are cancelled in your Apple ID settings. Website purchases have a 14-day money-back guarantee.