Outlook Suggested Replies AI Toggle: How to Enable for English Inbox

Outlook can suggest short replies to emails you receive, saving time on routine responses. This feature uses AI to analyze incoming messages and offers three pre-written reply options. The Suggested Replies toggle is available in Outlook for Microsoft 365 and Outlook on the web, but it only works when your mailbox language is set to English. This article explains how to enable the toggle and what to do if the option is missing or grayed out.

What the Suggested Replies Feature Does

Suggested Replies is an AI-powered feature in Outlook that scans the body of incoming emails and generates three short response options. For example, if someone asks “Can we meet at 3 PM?”, Outlook might suggest “Yes, that works,” “No, I’m busy then,” or “Let me check my calendar.” The user can click any suggestion to insert it directly into the reply compose window.

The feature is available in Outlook for Microsoft 365 (desktop version) and Outlook on the web. It is not available in Outlook 2021, 2019, or earlier standalone versions. The AI model requires the mailbox language to be set to English — specifically English (United States), English (United Kingdom), English (Canada), English (Australia), or English (India). If the mailbox language is any other language, the toggle will not appear or will be grayed out.

Prerequisites for Using Suggested Replies

Before enabling the toggle, verify these three conditions:

• Your Microsoft 365 subscription must include Exchange Online. Suggested Replies is a cloud-based feature that requires a connection to Microsoft servers.
• Your mailbox language must be set to one of the supported English locales. You can check this in Outlook on the web under Settings > General > Language and time.
• Your Outlook client must be updated to the latest version. For desktop, go to File > Office Account > Update Options > Update Now.

Steps to Enable Suggested Replies in Outlook Desktop

Follow these steps to turn on the Suggested Replies toggle in the Outlook desktop application.

1. Open Outlook and go to File > Options
   Click File in the top-left ribbon, then click Options at the bottom of the left pane. The Outlook Options dialog box opens.
2. Select the Mail tab
   In the Outlook Options dialog, click Mail in the left navigation list. This page contains settings for message composition and replies.
3. Scroll to the Message format section
   Scroll down until you see the heading “Message format.” The Suggested Replies toggle is located directly below this heading.
4. Check the box for Show suggested replies
   Click the checkbox next to “Show suggested replies” to enable the feature. A checkmark indicates it is turned on.
5. Click OK to save
   Click OK at the bottom of the dialog to apply the change. Close and reopen Outlook if the toggle was previously grayed out and you changed the language setting.

Steps to Enable Suggested Replies in Outlook on the Web

If you use Outlook in a browser, enable the feature through the Settings panel.

1. Sign in to Outlook on the web
   Go to outlook.office.com and sign in with your Microsoft 365 work or school account.
2. Open Settings
   Click the gear icon in the top-right corner of the page to open the Settings pane.
3. Go to Mail > Compose and reply
   In the Settings pane, click Mail, then click Compose and reply from the sub-navigation.
4. Turn on Suggested replies
   Under the “Suggested replies” section, toggle the switch to On. The switch turns blue when enabled.
5. Close the Settings pane
   Click the X in the top-right corner of the Settings pane to close it. The feature takes effect immediately — no restart required.

How to Check and Change the Mailbox Language

If the Suggested Replies toggle is missing or grayed out, the mailbox language is likely not set to English. Check and change it in Outlook on the web.

1. Open Outlook on the web and go to Settings
   Click the gear icon, then click View all Outlook settings at the bottom of the Settings pane.
2. Select General > Language and time
   In the left pane, click General, then click Language and time.
3. Change the language to English
   Under “Language,” select an English locale such as English (United States) or English (United Kingdom) from the dropdown list.
4. Click Save
   Click Save at the top of the page. The page refreshes with the new language. Return to Compose and reply to enable Suggested Replies.

If the Toggle Still Does Not Appear

Outlook desktop shows “Suggested Replies is not available for your mailbox”

This message appears when the mailbox is hosted on an on-premises Exchange server or a standalone Exchange plan without the AI feature. The only solution is to switch to a Microsoft 365 mailbox with Exchange Online. Contact your IT administrator to verify your subscription.

Toggle is grayed out in Outlook on the web

A grayed-out toggle indicates that the mailbox language is not set to a supported English locale. Follow the steps in the previous section to change the language. After changing the language, refresh the browser tab and check the toggle again.

Suggested replies do not appear on emails after enabling

The feature only activates on emails that are short and written in English. It will not show suggestions for messages longer than about 150 words, emails with multiple recipients, or emails that contain sensitive content such as passwords or financial data. Also, the feature requires an active internet connection — offline mode disables the AI processing.

Suggested Replies Availability: Desktop vs Web vs Mobile

Item	Outlook Desktop (Microsoft 365)	Outlook on the Web
Feature toggle location	File > Options > Mail > Message format	Settings > Mail > Compose and reply
Language requirement	English mailbox language	English mailbox language
Internet connection required	Yes	Yes
Available offline	No	No
Works with on-premises Exchange	No	No
Supports non-English mailboxes	No	No

Outlook mobile apps (iOS and Android) also support Suggested Replies, but the toggle is enabled by default and cannot be turned off from the mobile settings. To disable it on mobile, you must turn off the feature in Outlook on the web or the desktop client, and the mobile app will sync the setting.

Now that the Suggested Replies toggle is enabled, you can click any suggested reply at the bottom of an email reading pane to insert it. The feature works best for short, yes-or-no questions and scheduling confirmations. To customize which replies appear, no settings exist — the AI selects them automatically based on the email content. For more control over response templates, consider using Quick Parts or custom email templates in Outlook.