Incorrect synchronization between Outlook Tasks and iOS Reminders

Copper Contributor

   If on Windows devices the standard app for tasks is Outlook (or Microsoft ToDo), then for iOS devices the standard app for tasks is Apple build “Reminders”.

   Between Outlook tasks (Microsoft ToDo) and iOS Reminders, there is synchronization of tasks and it works not bad, but there are two small issues. I want to show them to you in a five-minute video with I made simultaneously on iPhone, iPad and Laptop for clarity. So watch these videos at the same time. It's faster than explaining them in text.

Sync issues between Outlook tasks and iOS Reminders — OneDrive (

1. When I change the due date on (or on Outlook tasks or on Microsoft ToDo) of any task from “today" to “no date" — synchronization time from “today" to “no date" on iPhone and iPad don't change!

2. After I delete all reminders from (or from the iPhone) - they are not deleted from the iPad. Even if we wait whole day, nothing will be removed.

   To reduce your time, I want to inform you that I have been writing about these 2 issues of synchronizing Microsoft ToDo support for a whole year :( And these issues has long been known, poor synchronization between Microsoft and Apple protocols. But Apple support says that the problem is on the Microsoft side.

7 Replies

Hi George,
Happy workday to you. At the Microsoft Ignite Virtual event, the first week of November, Microsoft announced many new updates to the Microsoft To-Do. Syncing the apps was one of the features they mentioned.

Try updating the app on all devices to see if it fixes the issues.


  Hi Teresa_Cyrus,

  I have the latest version Microsoft ToDo application but new updates didn't resolve these issues :(  Moreover, I do not use MS ToDo, because I manage tasks with MS Outlook on laptop and on iOS devices the standard app for tasks is Apple build “Reminders”.

As you can see in this bundle there is no Microsoft To Do, why? I'll explain now.


  The success of any planning is clarity, when the calendar and tasks are visually on the same monitor - this is exactly what is implemented in Outlook. Look at the screen! Tasks for today / tomorrow, etc.

  In this visibility the key to successful planning! And when Meetings from the calendar in one place - and tasks in another program - the focus and clarity are lost, and all the value of Outlook is lost.

  Not only lose focus and clarity when you start using Microsoft To Do, but also Microsoft To Do has a different logic for working with tasks. For example, there is the basis of the day - "My Day", which is not visible in Outlook and iOS Reminders. Not only is it not visible in Outlook - this idea unsuccessful, because it is inconvenient. But the focus on tasks in both Outlook and iOS Reminders on "Today" is what we need! In this sense, iOS Reminders is logically closer to Outlook tasks than Microsoft To Do! That's why that in this combination, Microsoft To Do is just superfluous. You can check google because a lot of people would like to sync their Outlook tasks exactly with iOS Reminders for the same reason.

  That is why It would be useful for everyone to resolve these two small issues between Outlook Tasks and Apple build Reminders on iOS. Let users have choice combine Outlook with applications they want with, including Apple build “Reminders”.

Hi @_Mr_George


The Apple Reminder app looks good. It shows the Calendar and Tasks in one desktop view.


I suggest giving Microsoft the feedback to "incorporate this view as part of their existing products" instead of syncing with third-party apps. For example, many users have expressed that they would like MyDay to evolve with functionality to display multiple days instead of just Today.  It is being considered.  


My perspective is Microsoft’s focus is investing in their Online applications.  Again, I like this view and would like to see it become available in MS To Do.

@Teresa_CyrusThis application is not Apple Reminder - this is MS Outlook! Go to your Outlook, go to the calendar section, among them select the MS Exchange calendar -> then add a task display -> and you will have exactly the same look!

  As you can see, this view is already available in MS Outlook, but the synchronization of tasks between Apple Reminder has bugs that I described in my first post.


Two messages above, I explained in detail why not all people use MS To Do if you manage your tasks through MS Outlook. For this reason, much better to give people the freedom of choose which program to combine their MS Outlook with, MS To Do or with Apple Reminders.

  I want to add some additions.
  When in iOS Reminders I create several tasks with due date of "today" with reminders also today - they are synchronized with Outlook and this can be seen under the calendar. But when in Outlook I go to the Tasks tab and then return to the Calendar again, all tasks disappear under the calendar. How it looks: 

Last 2 issues between iOS Reminders and Outlook Tasks — OneDrive (
  I tested this issues on several Microsoft accounts and on two Outlook 2019 and 2021 - this error is present everywhere. The same result in safe mode - tasks with a deadline of today and a reminder(!) today disappear.

   BUT, I have some important additions! "Disappearing Tasks" effect only occur when the creation is done from the "reminder app" (the standard app for tasks on iOS Apple build “Reminders”)! If I make tasks in Microsoft To Do on iOS - this bug is not present in Outlook on Windows. Which means that there is some incorrect synchronization between Outlook Tasks and iOS Reminders. It looks like this issue is related to that issue what I already pointed in first message of this topic! I think this additions can help developers to fix these bugs

Hello, did you manage to resolve the issue?

It's even more annoying if you have multiple Apple devices (phone + tablet).