Why doesn't TODO stop displaying a reminder when I have closed it???

If the task is marked Completed but merely remains visible in Outlook, hide completed tasks from the current view; if it is actually generating another alert, check and remove its Repeat setting.

If the completed task is only still displayed

Completed tasks are retained rather than deleted, and some Outlook views deliberately show them.

Classic Outlook for Windows — identifiable by the File tab:

1. Open Outlook’s Tasks view.
2. Select View > Change View.
3. Choose Active, Next 7 Days, or Overdue. These views exclude completed tasks.

If it appears in the To-Do Bar:

1. Right-click the Type a new task box and select Filter.
2. Open Advanced.
3. Add:
   • Date Completed > does not exist
   • Flag Completed Date > does not exist
4. Select OK.

These are Microsoft’s documented filters for hiding completed tasks in classic Outlook. ^1^

Microsoft To Do or new Outlook:

• Open the task’s original list.
• Collapse the Completed section, or use the list option to hide completed tasks.
• Do not use the Completed smart list when looking for outstanding work; that list intentionally contains completed items. ^2^ ^3^

Thus, seeing the item crossed out or under Completed does not mean To Do failed to close it—it means the selected view retains completed history.

If a notification or apparently new task keeps returning

Open the task and inspect Repeat:

1. Select the task to open its details.
2. Find Repeat.
3. If it is set to daily, weekly, monthly, yearly, or custom, remove recurrence if the task should end permanently.
4. Also inspect Remind me and remove any reminder that is no longer required.

A repeating task can produce a subsequent occurrence after the current occurrence is completed. Due dates, reminders, and recurrence are separate task settings. ^4^

Compare the displayed item carefully:

• Same task, shown as completed: this is a view/filter issue.
• Same title but unchecked, with a later date: this is likely the next repeated occurrence.
• Original task still unchecked everywhere: completion did not synchronize.

If Outlook still shows it as incomplete

Closing Outlook has already failed to change the behavior, so check the server copy instead:

1. Open Microsoft To Do on the web using the same Microsoft account as Outlook.
2. Locate the task in its original list—not only in My Day.
3. Check whether its circle is marked complete.
4. If the web copy is complete but Outlook shows it incomplete, the issue is local to Outlook’s display or synchronization.
5. If the web copy is also incomplete, mark it complete there and allow it to synchronize.

To Do normally updates automatically, and its tasks are stored on Exchange Online and synchronize with Outlook Tasks. ^5^

Also verify that Outlook and To Do use the same Microsoft account; otherwise, they can display different copies or task lists. ^6^

If the web copy is correct but Outlook continues firing reminders for the completed copy, report it from Outlook through Help > Report a problem, including whether this is classic Outlook or new Outlook and whether the item is recurring.

References

1. Customize the To-Do Bar in classic Outlook | Microsoft Support
2. [Web](https://support.microsoft.com/accessibility/todo/use-a-screen-reader-to-work-with-lists-in-to-do#show-or-hide-completed-tasks)
3. [New Outlook](https://support.microsoft.com/outlook/create-and-manage-task-lists-with-my-day-in-outlook#about-default-and-smart-lists-in-new-outlook)
4. Add due dates and reminders in Microsoft To Do
5. Syncing your Microsoft To Do account | Microsoft Support
6. Using Microsoft To Do with Outlook Tasks | Microsoft Support