Outlook Follow-Up Reminder If No Reply: 3 Ways

Why there is no built-in Outlook follow-up reminder if no reply arrives

Outlook reacts to things that happen: a message arrives, a flag comes due. A reply that never arrives is not an event, so a rule has nothing to react to. Every approach below works around this: you set a timer and check yourself, or an automation looks for a reply later and alerts you only if there is none.

The options differ between classic Outlook, the new Outlook for Windows and Outlook on the web. Where Microsoft documents a difference, this guide says so.

Option 1: Flag the email for yourself

1. Classic Outlook: set the reminder before you send

In the new message, on the Message tab, in the Tags group, select Follow Up and then Add Reminder. Check Flag for Me, set a due date and a reminder time, and select OK. In the Flag to box, you can type your own text. With an IMAP account, you can't change the flag text or set start and due dates.

2. New Outlook and Outlook on the web: flag after sending

At the time of writing, a Microsoft Q&A moderator answer says the new Outlook can't set a reminder before sending. Send the email, open Sent Items and flag it there. Then set the reminder time on the item under Flagged emails in To Do. In current builds of the new Outlook, you reach it through the To Do icon or My Day.

3. Clear the flag when the reply comes in

The flag doesn't know whether the client replied. When a reply arrives, clear the flag on your sent message, or the reminder fires anyway.

Example
Sent: proposal v2 to Dana at Example Logistics LLC, Tuesday
Flag for Me: due Friday, reminder Friday 9:00 AM
Flag text: Follow up: proposal v2, decision on scope
Flag for Recipients: off

Option 2: One list of everything you are waiting on

A search folder collects your flags in one place. In the new Outlook, go to Search Folders, select the more options button and choose Create new search folder. Pick the type Flagged for follow-up, turn on Filter to specific folders and select Sent Items. The result is a list of sent emails you are still waiting on. In classic Outlook, the steps differ. Microsoft's search folder guide in the sources covers both.

The new Outlook only offers predefined search folder types. Advanced custom search folders are only supported in classic Outlook. For a view of everything from one client, see how to find all emails from a client in Outlook.

Ten-minute review, once a week
1. Open the search folder with your flagged sent items.
2. Has the client replied? Clear the flag.
3. Is it overdue? Send a short follow-up now, not later.

Option 3: Let Power Automate check for a reply

For important messages, a cloud flow can wait a few days, look for a reply and remind you only if there is none. Power Automate is Microsoft's service for such automated workflows, called flows. You create one at make.powerautomate.com as an Automated cloud flow: a trigger, an event such as flagging an email, starts it, and the actions after it run on their own. This flow uses the Office 365 Outlook connector. Treat the steps below as an outline: Microsoft documents each operation, but not this exact combination.

1. Trigger: When an email is flagged (V3)

Set Folder to Sent Items, so the flow only starts for sent messages you flag.

2. Wait: Delay

Add a Delay, for example three days. A flow run can last at most 30 days.

3. Look for replies: Get emails (V3)

Folder: Inbox. Use Search Query, for example from:dana@example-logistics.com, and raise Top, the maximum number of emails returned, above its default of 10, for example to 50. The From and Subject filters only check the first 250 emails in a folder. Search Query searches the whole folder.

4. Match the thread: Filter array

Keep only emails whose Conversation Id matches the flagged message, so an unrelated email from Dana doesn't count.

5. Remind yourself: Condition and Send an email (V2)

If the list is empty, send yourself an email with the original subject. Write the follow-up to the client yourself. Automatic nudges rarely read well.

Flow at a glance
When an email is flagged (V3), Folder: Sent Items
Delay: 3 days
Get emails (V3), Folder: Inbox, Search Query: from:client address, Top: 50
Filter array: Conversation Id equals trigger Conversation Id
Condition: result empty, then Send an email (V2) to yourself

Know the limits. The trigger also fires when a flagged email is changed, for example replied to, which can start a second run and send you a duplicate reminder. In rare cases it fires up to an hour late. A reply from the client's colleague doesn't match the search query, and a reply sent as a new email has a different Conversation Id, so the flow misses both. Test it once before relying on it: flag an email to a colleague, point the search query at their address and shorten the delay to a few minutes. For wording, see these client follow-up email templates.

What Copilot in Outlook can and can't do here

Microsoft lists drafting emails, summarizing threads and tone coaching as Copilot features in Outlook, even without the Microsoft 365 Copilot add-on license. For eligible users, Copilot Chat in Outlook answers questions about your inbox, calendar and meetings from a limited set of data. The add-on license adds broader access across Microsoft 365.

That helps in two places. Before a follow-up, let Copilot summarize the thread and draft a short nudge that you edit. As a check, ask Copilot Chat "Which emails did I send to Example Logistics this month that have no reply yet?" and verify the answer in Sent Items. Microsoft doesn't document this use.

Microsoft's documentation doesn't describe a Copilot feature that watches a sent email and reminds you when no reply arrives. Copilot responds when you ask. What you see depends on your Outlook version, license and admin settings.

Where flags and flows stop with several clients

For a handful of clients, flags plus a weekly review are enough. With more parallel engagements, three problems show up.

A reply is not an answer

"Thanks, we'll check internally" counts as a reply. You clear the flag, the flow finds a reply, and the question is still unanswered.

Commitments don't only live in your sent emails

Promises like "We'll send the export by Friday" come up in calls or in the client's emails. No flag catches them. See how to track client commitments.

The view is per email, not per client

Flags don't show where an engagement stands, and they live in one mailbox. If a colleague takes over, the context stays behind.

Where aenuma fits

The steps above work well as long as you set them up yourself and the number of clients stays small. If follow-ups slip across many clients, aenuma can build this workflow for you: we connect your mailbox with the tools you already use, set up the agreed rules, and test them with representative examples. What may happen automatically and when a person checks it is agreed before we start, and messages to your clients need your approval.

You don't have to use the aenuma app for this. If you would rather keep track of open items yourself, the app lists who owes what per client, each item with its source. More on tracking follow-ups.

Frequently asked questions

Can Outlook automatically send a follow-up email if there's no reply?

Not with built-in features. Flags only remind you. A flow could send it, but with clients a follow-up you write yourself usually works better.

Why can't I set a reminder while writing an email in the new Outlook?

The option isn't there at the time of writing (see Option 1, step 2). Flag the email in Sent Items and set the reminder in To Do. Classic Outlook still offers Follow Up and Add Reminder.

Do I need a Copilot license for this?

Not for flags or search folders. Microsoft 365 licenses include Power Automate with standard connectors such as Office 365 Outlook. Copilot drafting and summarizing in Outlook work without the add-on license. Broader data access requires it.

Does Flag for Recipients remind the client?

In classic Outlook it adds a flag and, by default, a reminder to the recipient's copy if they use Outlook. Microsoft itself advises using it with discretion.

Sources

Flag email messages for follow up (classic Outlook)
Send an email message with a follow-up reminder
Microsoft Q&A: Reminders attached to emails (new Outlook, reminder before sending)
Microsoft Q&A: Flag reminder for recipient in new Outlook, My Day / To Do workaround
Use search folders to find messages or other Outlook items
Feature comparison between new Outlook and classic Outlook
Office 365 Outlook connector reference (triggers, Get emails (V3), known issues)
Power Automate seeded licenses: standard connectors included with Microsoft 365
List of standard tier connectors (Office 365 Outlook)
Delay action: count and unit (built-in Schedule action, documented for Azure Logic Apps)
Use data operations: Filter array
Power Automate limits: run duration and retention
Use the $search query parameter in Microsoft Graph (from, subject)
Microsoft Copilot overview: Copilot features in Microsoft 365 apps
Overview of Microsoft Copilot Chat: grounding in Outlook
Chat with Copilot in Outlook
Microsoft 365 Copilot release notes (July 2026: Copilot Chat in Outlook over inbox and calendar)

By Joshua Schütt, founder of aenuma. Last updated: October 2026. Examples are fictional.

How to get an Outlook follow-up reminder when a client doesn't reply