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How to set up automatic replies in Office 365 and Outlook
TL;DR
Set automatic replies in Outlook on the web, Outlook desktop, the Exchange admin center (EAC), or with Microsoft 365 Copilot.
Admins configure replies for any user or shared mailbox directly in the EAC; shared mailboxes must be set up this way, since they have no sign-in of their own.
Use transport rules or PowerShell for conditional or bulk automated responses.
Microsoft 365 sends only one automatic reply to each sender for as long as Automatic Replies stays switched on. Turning it off and back on resets who's been replied to; there's no automatic time-based reset.
If replies aren't working, check external reply settings, mailbox rules, and shared mailbox configuration first.
Automatic replies let Outlook and Microsoft 365 send messages on your behalf when you're unavailable. They're most often used for out-of-office notifications, but they can also confirm receipt of messages, direct people to shared inboxes, or explain response delays during busy periods.
A quick note on naming: this guide says "Microsoft 365" throughout, since that's what Microsoft has called it since 2020. If you're still on an Office 365 Enterprise, Education, or Government plan (E1, E3, E5), the steps below are identical. Microsoft only renamed the plans that most small and mid-size businesses actually use; a handful of legacy enterprise SKUs kept the old name.
Automatic replies help keep communication consistent when teams aren't available, but the setup process varies across mailbox types and admin permissions. The table below is the fastest way to find the right method; the sections after it walk through each one step by step. In Microsoft 365, automatic replies can be set by individual users or configured centrally by IT admins. The behavior depends on where the reply is created: Outlook on the web, Outlook desktop, or the Exchange admin center. Each option handles timing, internal and external messages, and rule-based automation slightly differently.
Which setup method should you use?
Mailbox type | Where to set it | Who can do it |
|---|---|---|
Your own mailbox | Outlook on the web, or Outlook desktop (Classic or New; menu path differs, see below) | Any user, for their own mailbox |
Shared mailbox | Exchange admin center (recommended); delegated access in Outlook on the web (if Full Access is granted) | Exchange Administrator, Global Administrator, or a user with Full Access |
Another user's mailbox (they're unavailable) | Exchange admin center | Exchange Administrator or Global Administrator |
Conditional or bulk replies across many mailboxes | Transport rules or PowerShell | Exchange Administrator or Global Administrator |
Why use automatic replies in Microsoft 365?
Automatic replies are useful whenever you need to set clear expectations about response times. Most people use them for annual leave or public holidays, but they're also effective in day-to-day operations. There are several reasons for using auto responses in Outlook for Microsoft 365.
Common use cases include:
Planned absence: Annual leave, parental leave, training days, or company-wide shutdowns.
Short-term unavailability: Meetings, travel, or periods where inbox monitoring is limited.
Shared mailboxes: Letting customers or internal teams know their message has been received and when they can expect a reply.
High-volume periods: Seasonal peaks, support backlogs, or situations where teams can’t respond at normal speed.
Routing messages: Directing people to alternative contacts, service desks, or ticketing systems when the primary mailbox isn’t monitored.
Configured correctly, automatic replies reduce uncertainty, lower follow-up volume, and help teams maintain a predictable communication experience, even when someone isn’t available.
By complementing them with professional email signatures, your business emails can become powerful drivers of engagement, amplifying your messages and expanding your reach.
How do you write an effective automatic reply?
To ensure that your auto responses are effective and professional, here are some tips to keep in mind:
Keep it concise and clear: An automatic reply is a snippet, not an email. A recipient should understand it at a glance, without wading through extra detail.
Use a friendly and professional tone: An automatic reply still represents your brand. Aim for a tone that's warm without losing professionalism, even though nobody wrote it in the moment it sends.
Include relevant information: Give the sender what they actually need: an alternative contact and the reason you're away. That's what lets them act instead of just waiting.
Don't forget to turn it off: Switch it off when you're back. A live automatic reply on a returned colleague sends a confusing signal to anyone still hearing from it.
How to set up automatic replies in Outlook on the web
Outlook on the web gives users the most straightforward way to turn on automatic replies. The feature sits in the mailbox settings and supports scheduled time ranges, internal/external messages, and simple routing instructions.
Open Outlook on the web. Go to https://outlook.office.com and sign in with your Microsoft 365 account.
Open Settings. Select the Settings icon in the top-right corner, then choose View all Outlook settings.
Go to Automatic replies. Navigate to Mail > Automatic replies.
Turn on automatic replies. Enable Automatic replies on.
Optionally set a start and end time so replies activate and stop automatically.
If you don't set a timeframe, the reply stays active until you switch it off manually.
Write your messages. Add the reply you want internal users to receive. If you want a different message for external senders, select Send replies outside your organization and enter the text.
Choose optional settings. Outlook on the web also allows you to:
Block out your calendar for the selected period
Decline new meeting invitations
Decline and cancel existing meetings during the timeframe
Save your changes. Select Save to apply the settings.
Automatic replies start immediately unless you've scheduled a specific date range.
How to set up automatic replies in Outlook desktop
Outlook desktop includes its own automatic replies feature, but "Outlook desktop" now means two different interfaces with two different menu paths. Classic Outlook uses the File menu; New Outlook for Windows uses a settings pane closer to Outlook on the web. Use the section that matches what's actually on your screen.
Classic Outlook for Windows
Open Outlook. Launch the classic Outlook desktop application and sign in if required.
Open the Automatic Replies menu. Go to File in the top-left corner. Select Automatic Replies (Out of Office).
Turn on automatic replies. In the Automatic Replies window, choose Send automatic replies.
Set a timeframe (optional). If you want replies to start and stop automatically, select Only send during this time range and choose the start and end dates.
Write your messages
Use the Inside My Organization tab to write the message for internal recipients.
Use the Outside My Organization tab to write a message for people outside your organization if needed.
Apply and close. Select OK to save and activate the settings.
Automatic replies will run until the end of your specified timeframe or until you return to this menu and switch them off manually.
New Outlook for Windows
New Outlook doesn't have a File menu automatic-replies option at all. Instead, per Microsoft's own instructions:
Open View settings. On the View tab, select View settings.
Go to Accounts. Select Accounts > Automatic Replies, then choose the account to configure if you have more than one.
Turn on automatic replies. Enable the toggle, then optionally select Send replies only during a time period and set start and end times.
Write your messages. Enter the internal message under Send automatic replies inside your organization. To also reply to people outside your organization, select Send replies outside your organization and add a separate message. (Microsoft recommends limiting this to Send replies only to contacts where that option is available, since sending to everyone outside your organization also replies to newsletters and other automated senders.)
Save your changes.
If these steps don't match what you see, check Microsoft's current instructions directly. Microsoft has been actively developing New Outlook, and past versions of this guidance have moved before.
Tip
If you're troubleshooting someone else's automatic reply and the steps above don't match their screen, check whether they're on Classic or New Outlook before assuming something's broken. The two versions look different enough that this is a common source of "it's not working" reports that turn out just to be a menu mismatch.
How to enable auto responses in Microsoft 365
Admins can configure automatic replies for any mailbox directly in the Exchange admin center (EAC). This is useful when a user is unavailable, a shared mailbox needs a standard response, or a department requires consistent messaging.
Follow these steps:
Open the Exchange admin center. Go to https://admin.exchange.microsoft.com and sign in with the relevant admin role (Exchange Administrator or Global Administrator).
Go to Mailboxes. In the left-hand navigation, select Recipients > Mailboxes.
Choose the mailbox. Select the user or shared mailbox you want to configure. Choose Settings in the right-hand panel.
Open Automatic replies. Under Mail flow settings, select Automatic replies.
Turn on automatic replies. Enable Automatic replies for the selected mailbox.
You can apply the reply indefinitely, or
Set a specific start and end time.
Write the reply messages. Enter the internal message. If a different external message is needed, enable Send replies outside the organization and add the external text.
Save the configuration. Select Save to apply the changes.
Automatic replies start immediately unless you've scheduled a specific timeframe. Users cannot override admin-configured automatic replies unless you switch them off at the admin level.
How to set up an auto response for a shared Outlook mailbox
Shared mailboxes don't have their own sign-in, so users can't set automatic replies themselves. Automatic replies must be configured through the Exchange admin center (EAC) or by using delegated permissions in Outlook on the web.
Method 1: Configure automatic replies in the Exchange admin center
Open the Exchange admin center. Go to https://admin.exchange.microsoft.com and sign in with an admin account.
Go to Recipients. Select Recipients > Mailboxes.
Find the shared mailbox. Locate the shared mailbox in the list and select it.
Open Automatic replies. In the right-hand panel, go to Mail flow settings > Automatic replies.
Enable automatic replies. Turn on Automatic replies.
Set a timeframe if needed
Or leave it active indefinitely
Add the message content. Enter the internal and external reply text. Most shared mailboxes send the same message to everyone, but separate messages are supported.
Save your changes. Select Save to activate the settings.
This is the most reliable way to control auto-responses for shared mailboxes.
Method 2: Configure replies using delegated access (Outlook on the web)
If users have Full Access permissions to the shared mailbox, they may be able to set automatic replies through Outlook on the web.
Open Outlook on the web.
Select your profile photo.
Choose Open another mailbox and select the shared mailbox.
Go to Settings > View all Outlook settings > Mail > Automatic replies.
Turn on automatic replies and add the message content.
Save the changes.
Tip
This option isn’t always available, depending on tenant configuration and permission level. The EAC method is more reliable.
How to set automatic replies for another user
IT admins often need to set automatic replies on behalf of users who are unavailable or unable to access their mailbox. This is done through the Exchange admin center (EAC) or by temporarily granting mailbox access.
Method 1: Use the Exchange admin center (recommended)
This is the simplest and most controlled option.
Open the Exchange admin center. Visit https://admin.exchange.microsoft.com and sign in with an Exchange Administrator or Global Administrator account.
Go to Recipients > Mailboxes. Locate the user's mailbox.
Open Automatic replies. In the right-hand settings panel, select Mail flow settings > Automatic replies.
Enable automatic replies. Turn on Automatic replies.
Choose a timeframe if required
Or leave the reply active until turned off manually
Add the reply messages. Enter the internal reply. Add an external reply if needed.
Save your changes. Select Save to apply the configuration.
Changes take effect immediately, and users cannot override settings configured at the admin level.
Method 2: Temporarily assign mailbox access
If you prefer to configure the reply in Outlook on the user's behalf, you can grant access and set it through Outlook.
Option A: Use Full Access permissions
In the EAC, grant yourself Full Access to the user's mailbox.
Open Outlook on the web.
Select your profile photo and choose Open another mailbox.
Open the user's mailbox.
Go to Settings > View all Outlook settings > Mail > Automatic replies.
Set the message and save your changes.
Option B: Reset the user's password (least preferred)
Only used in exceptional cases and should follow internal access policies. Once signed in, configure automatic replies normally, then force a password reset.
To configure automatic replies for someone else, you need one of the following:
Exchange Administrator role
Global Administrator role
Full Access to the specific mailbox
"Resetting someone's password just to set an auto-reply breaks something people don't think about: you're now signed in as them, in their mailbox, and there's no way to tell that apart from them doing it themselves. IT might shrug it off as a minor annoyance, but anyone who deals with compliance won't, as it's an audit-trail gap. And if it's a frequent issue for the same person, it can't be passed off as just bad luck. Something in the delegation model needs fixing, and another password reset isn't going to do it."
What are the advanced options for automatic replies?
Most automatic replies are set through Outlook or the Exchange admin center. For more complex scenarios, IT teams can use transport rules, PowerShell, or Microsoft 365 Copilot to create or manage automated responses with specific conditions. These options are useful when messages need to be routed, filtered, or replied to based on defined criteria, or when someone would rather manage a reply conversationally than through settings menus.
Using transport rules for conditional auto-responses
Transport rules let you create targeted auto-responses based on sender, recipient, keywords, or message type. This is useful for scenarios where standard automatic replies won’t apply.
Common use cases include:
Replying only to messages sent to a specific address (e.g., a campaign inbox)
Sending a confirmation message when users email a monitored mailbox
Returning a structured response when emails contain certain phrases
Creating different auto-replies for internal and external senders
To create a transport rule:
Open the Exchange admin center. Go to https://admin.exchange.microsoft.com.
Go to Mail flow. Select Mail flow > Rules.
Create a new rule. Choose Add a rule and give it a clear name.
Set the conditions. Define the conditions that trigger the auto-response (e.g., sent to a specific mailbox).
Add the action. Select Apply a message response and enter the text you want to send.
Review and save. Confirm the settings and save the rule.
Tip
Transport-rule responses do not support rich HTML formatting. They also apply at the server level, so make sure they don’t conflict with user-level automatic replies.
Using PowerShell for automated replies
PowerShell provides more granular control and is useful for bulk changes or scripted workflows.
Enable automatic replies with PowerShell
First, connect to Exchange Online PowerShell:
Connect-ExchangeOnlineThen run:
Set-MailboxAutoReplyConfiguration -Identity "[email protected]" -AutoReplyState Enabled -InternalMessage "Internal reply text" -ExternalMessage "External reply text"Set a reply with a date range
Set-MailboxAutoReplyConfiguration -Identity "[email protected]" -AutoReplyState Scheduled -StartTime "MM/DD/YYYY 09:00" -EndTime "MM/DD/YYYY 17:00" -InternalMessage "Internal reply" -ExternalMessage "External reply"Disable automatic replies
Set-MailboxAutoReplyConfiguration -Identity "[email protected]" -AutoReplyState DisabledTip
If you set -ExternalMessage without also specifying -ExternalAudience, Microsoft's own parameter reference confirms it defaults to All, meaning the reply goes to every external sender, including newsletters and automated senders. That's more permissive than the Outlook GUI's own recommendation elsewhere on this page, which suggests limiting external replies to known contacts. Add -ExternalAudience Known explicitly if you want that same restriction from PowerShell.
Using Microsoft 365 Copilot to manage automatic replies
Microsoft 365 Copilot can set up, update, or turn off automatic replies from a chat prompt, without opening the settings menus above.
This works from the Microsoft 365 Copilot app or the Copilot side pane inside Outlook, on web, Windows, Mac, iOS, and Android:
Open Microsoft 365 Copilot, either as its own app or the Copilot side pane inside Outlook.
Type a prompt such as "Set up automatic replies for tomorrow."
Review the draft Copilot prepares. It bases the wording on your previous automatic-reply style and tone, as well as any dates, delegate names, or message details you've provided in the conversation. If you opened Copilot from an email already in view, such as an approved vacation request, it can pull the relevant dates from that message automatically.
Confirm the draft to apply it.
Use follow-up prompts like "Update my automatic reply" or "Turn off my automatic replies" to manage it from the same conversation.
This is currently available in English only, and needs a Microsoft 365 Copilot license. For anyone without one, or for shared mailboxes and setting replies on someone else's behalf, use the EAC methods above instead.
When to use advanced configuration
Advanced options are best suited for situations where:
Standard automatic replies don't meet the requirement
Multiple mailboxes need uniform responses
You need conditional logic for responses
You're automating mailbox provisioning workflows
You want to manage replies at scale without UI interaction, or conversationally through Copilot
Why isn't my automatic reply working?
Automatic replies in Microsoft 365 usually work without issues, but problems can occur due to mailbox settings, policy restrictions, or conflicting rules. The points below cover the most common causes and how to resolve them.
Automatic replies aren’t being sent
Possible causes:
The feature is enabled in Outlook, but not saved correctly.
The reply is only set for internal recipients.
The mailbox is hidden from the global address list.
External replies are blocked by admin policy.
How to fix:
Check the settings in Outlook or the EAC to confirm automatic replies are actually enabled.
Verify Send replies outside your organization is turned on if external senders are expecting a reply.
Review mailbox properties to ensure the account isn't hidden.
Check tenant-wide external messaging policies in the Exchange admin center.
Automatic replies only send once
Microsoft 365 sends only one automatic reply to a given sender for as long as Automatic Replies stays continuously enabled. Microsoft's own documentation confirms that the "already replied to" list clears when Automatic Replies is switched off and back on, not automatically after a fixed number of hours. If someone's out for two weeks and never toggles the setting, a sender who emailed on day one still won't get a second reply on day 10. This is by design and cannot be adjusted.
How to fix:
Confirm expectations with the user or team.
If repeated responses are required, consider using transport rules instead of standard automatic replies.
Rules conflict with automatic replies
Inbox rules can override or block automatic replies in some cases.
How to fix:
Check the user's Rules settings in Outlook.
Disable or adjust rules that move messages on arrival, especially rules that redirect mail.
Test without any rules enabled to see if replies start working.
Shared mailbox replies aren’t triggering
This often happens when automatic replies are configured in Outlook instead of the Exchange admin center.
How to fix:
Configure replies directly in the EAC under Recipients > Mailboxes > Mail flow settings > Automatic replies.
Ensure the shared mailbox isn't set to forward messages, which can bypass the trigger.
Admin-configured replies aren’t updating
If you make changes in the EAC but the automatic reply still shows an older message:
How to fix:
Refresh the mailbox settings page to confirm the update saved.
Wait a few minutes; changes may take a short time to propagate.
Verify no PowerShell script or transport rule is overriding the behavior.
External senders aren’t receiving replies
Possible causes:
External replies disabled in the policy
The sender is on a blocked domain list
DMARC (Domain-based Message Authentication, Reporting, and Conformance) or SPF (Sender Policy Framework) failures causing mail to be handled differently
Transport rules affecting outbound behavior
How to fix:
Confirm external replies are enabled in the automatic reply settings.
Check Organization settings > External access.
Review mail flow rules to ensure nothing reroutes or blocks external responses.
Test with a verified external inbox to isolate the issue.
Every automatic reply still needs an email signature
None of the methods above touch what the message actually looks like once it lands: an automatic reply is still an email, and by default it goes out with whatever email signature (or none) is attached to the account or connector that sent it. That's easy to miss, because the setup lives in mail flow settings, not in the email signature settings most admins check first.
Key takeaway
Setting up an automatic reply and controlling what email signature it carries are two different settings, in two different places. Getting the first one right doesn't mean the second one is handled.
For a personal reply set in Outlook, that's usually fine, since the sender's own email signature already applies. It gets harder for the cases this guide spends the most time on: a shared mailbox with no email signature of its own, a transport rule reply that bypasses email signature settings entirely, or a reply sent on someone else's behalf where nobody's checked what identity it goes out under. Each of those is a message the organization sends without a person actively writing or checking it in the moment, which is the same governance gap that shows up everywhere else email signatures matter.
Exclaimer's cloud solution applies email signatures server-side, so a shared mailbox, a transport-rule reply, or an admin-configured out-of-office all carry the same consistent, on-brand email signature as every other message, without anyone having to remember to set one on each mailbox individually.
See how it works, or start a free trial to check your own shared mailboxes and auto-replies.
