Microsoft is adding a last-minute spelling check to New Outlook, which should make it harder to send an email with a glaring typo. A notice in the Microsoft 365 Admin Center says the app will be able to scan a message for spelling mistakes when you press Send, and stop to give you a chance to fix anything it finds before the email goes out.
The rollout begins in October 2026, but Microsoft’s timeline suggests most people won’t get it until mid-December at the earliest. As is typical with Microsoft 365 features, it will reach some users and organisations weeks before others.
What’s surprising is that this isn’t really a new idea for Outlook. The classic desktop version has offered an option to check spelling before sending for many years, hidden away in its mail settings. New Outlook, which Microsoft is steadily positioning as the default Windows mail client, didn’t have it. This is less an innovation than New Outlook catching up with a feature long-time users may have assumed was already there.
It still addresses a real problem. Microsoft Editor already underlines spelling and grammar errors as you type, but it’s easy to miss a red squiggle when you’re writing quickly or replying from a crowded inbox. A check at the moment you hit Send gives you a final safety net at the point where a mistake is most likely to slip through. New Outlook already offers an undo send option that briefly delays outgoing messages, and the two features work well together.
Microsoft will leave the check switched off by default, and you’ll need to turn it on in Settings. That’s sensible. Editor isn’t perfect, and it can flag correct words as mistakes, especially if your writing doesn’t match the language setting it expects. Anyone who writes “colour” or “organise” while Outlook is set to American English could quickly get tired of repeated warnings. For people who work in more than one language, or regularly use technical terms and brand names, that kind of interruption could be more annoying than useful.
People still using Outlook Classic won’t get this new version of the feature. Microsoft is prioritising new features for New Outlook while keeping the older client mostly limited to maintenance and security updates. For people who haven’t moved yet, each small feature like this adds another reason to consider switching. The larger question is whether Microsoft can bring over enough of Classic’s older functionality to make that switch feel like an upgrade rather than a compromise.
