You can use our Windows Desktop App to make corrections with LanguageTool in MS Outlook.
Please follow the installation process and note that the LT character should appear in your menu bar.
For more information and direct download, please visit our website.
Alternatively, you can use our desktop editors for Windows and macOS, to correct texts from Outlook via shortcut.
How to turn off Outlook’s built-in checker when using LanguageTool
If you're using LanguageTool for Windows with Microsoft Outlook, you may see Outlook's own spelling and grammar suggestions alongside LanguageTool’s. This can cause confusion or duplicate feedback.
To keep your writing environment focused and consistent, we recommend turning off Outlook’s native checker. Here's how to do that depending on the version you're using.
In classic Outlook:
Open a new message by clicking New Email
In the message window, go to the Review tab
Click Set Proofing Language…
Check the box Do not check spelling or grammar
Click Set As Default to apply the change
In Outlook 365:
Open a new message by clicking New mail
In the message window, go to the Options tab
Click Editor settings under the Editor section
In the Corrections section, uncheck all available options
Click OK to save your changes
Once these steps are complete, Outlook will no longer show its own spelling and grammar suggestions, allowing LanguageTool to take over and provide clear, uninterrupted feedback.