You missed the meeting and you are fairly sure nothing appeared. Before working through the settings, it is worth knowing that Outlook reminds you in two different ways, and they fail for different reasons: a Reminders window that Outlook draws itself, and a Windows notification handed to the operating system.

Which one you get depends on your Outlook and its settings. Classic Outlook shows its own Reminders window. New Outlook can do either — a separate pop-up window on top of other programs, or a Windows notification. That distinction decides both where to look and whether anything was recorded.

The settings that silence reminders

Check these causes in order.

  1. 1. Outlook is not running. Classic Outlook must be running to show reminders. New Outlook can notify you while closed only when its background-notification option and the matching Windows background permission are enabled.
  2. 2. Reminders are switched off inside Outlook. Classic Outlook: File → Options → Advanced → Show reminders. Turn on Show reminders on top of other windows too, or the window opens behind whatever you are working in and you never see it.
  3. 3. The calendar item has no reminder. File → Options → Calendar → Default reminders sets what new items get. An invitation accepted from someone else carries whatever they set, which is sometimes nothing.
  4. 4. Windows notifications for Outlook are off. Settings → System → Notifications, find Outlook, and check that the app is enabled and that Show notification banners is on. This only matters for the Windows-notification style of reminder.
  5. 5. Do not disturb is on. Windows suppresses banners while it is active, including automatically — during presentations, games, or full-screen apps, depending on your settings. What Do Not Disturb held back is its own question.
  6. 6. The reminders list is stuck. If reminders stopped for everything at once and the settings look right, the reminders store is the usual suspect. In classic Outlook the repair is to close it completely and start it once with the /cleanreminders switch, which clears and rebuilds the list. It discards pending reminders in the process, so run it when nothing is imminent. New Outlook has no equivalent switch.

How to tell whether anything reached Windows

The practical question is whether Outlook showed a reminder that you missed or showed no reminder at all. The two situations look identical afterwards but require different fixes.

If Outlook is configured for Windows notifications, press Win + N and look. Windows keeps a few notifications per application in the notification centre, so a reminder from an hour ago may still be there. If Outlook draws its own Reminders window instead, there is nothing to find: that window is Outlook’s, it never went through Windows, and once dismissed it leaves no trace outside Outlook’s own reminders list.

The mail alerts are a separate system again

Outlook’s new-mail alerts do go through Windows notifications, and they have their own switch: File → Options → Mail → Display a Desktop Alert. So it is entirely possible to get every email banner and no calendar reminders, which reads like Outlook is working and the calendar is broken.

Keeping the answer available

The notification centre holds three notifications per application by default — the per-app setting offers 1, 3, 5, 10 or 20 — and clicking or clearing one removes it. On a working day, an hour of email is enough to push a calendar reminder out of the panel. By the time you are asking whether you were reminded, the evidence is usually gone.

Notification Logger saves each Windows notification to your PC as it arrives and keeps the time it appeared. You can search the history, filter it by application or date range, and export it. The log shows whether an Outlook reminder appeared at 09:45.

The limit is the same one as everywhere on this page. It records what Windows was given. A reminder shown in Outlook’s own Reminders window never goes through Windows, so it is not in the log and not in the notification centre either — for that style of reminder, Outlook’s own list is the only record there is.

What to change so it does not happen again

  • Turn on Show reminders on top of other windows. A reminder hidden behind another window is easy to miss.
  • Set a default reminder time that gives you enough time to act. Fifteen minutes is the default; choose more if you need time to leave a building.
  • Check that Outlook starts with Windows, if you rely on it for meetings.
  • If you use new Outlook, choose the Windows-notification style rather than the separate window — it is the only one that survives long enough to check afterwards.

Sources

Frequently asked questions

Why do Outlook reminders not pop up even though Outlook is open?
Most often Show reminders is off under File → Options → Advanced, or the reminder is appearing behind other windows because Show reminders on top of other windows is not enabled. After that, check that Windows notifications for Outlook are on and that Do not disturb is off.
Do Outlook reminders appear in the Windows notification centre?
Only if Outlook is set to use Windows notifications. Classic Outlook shows its own Reminders window, which never reaches Windows and therefore never appears under Win + N.
How can I find out whether a reminder appeared at all?
Press Win + N — a recent one may still be in the panel, though it holds only a few per app. Beyond that window you need something that recorded notifications as they arrived; otherwise nothing distinguishes “no reminder was shown” from “a reminder was shown while you were away”.
I get email alerts from Outlook but no calendar reminders.
They are separate settings. Desktop alerts for mail are under File → Options → Mail; calendar reminders are under File → Options → Advanced and File → Options → Calendar. One working says nothing about the other.
What does the /cleanreminders switch do?
In classic Outlook it clears and rebuilds the reminders list, which is the standard repair when reminders stop for everything at once. It discards pending reminders, so use it at a moment when nothing important is due. New Outlook has no equivalent.
Does Do not disturb hide Outlook reminders?
It hides the banner. Windows can also enable Do not disturb automatically while you are presenting or in a full-screen application, which is why reminders sometimes go missing only during the meetings you most wanted them for.
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