To-Do requires Exchange?

Regular Contributor

I have someone who gets the error below when trying to open To-Do.  We have a number of people who are using it successfully.ToDoError.JPG

This particular person still has an OnPrem mailbox.  Is it a requirement for ToDo that the mailbox be online?  I would understand that for being able to sync tasks, but I was not expecting that it was a critical dependency.

Or is there something else that may be going on that is unrelated to the mailbox location?


6 Replies

Hi Adrian, glad to hear from you. 

You are correct: To-Do requires an EOL mailbox to store and sync tasks. 

I am sure I have read it in an official document, but I cannot find where.

Maybe someone other can find it...



"In addition to having a license for one of the suites above, you'll also need an Exchange Online mailbox for storage and sync to work.  As a result, we’re unable to support on-premise Exchange accounts if they don’t also have mailboxes ‘in the cloud’."

Thanks for sharing!


Since few days, without anychanges on my Office 365 E5 subscription, i get this message on the "Universal Windows" To-Do App , on some computer.

I tried to uninstall, reinstall, log with different account, then the bugged one.

Nothing works.

It is very anoying to have to use the "in browser" to-do instead of the desktop app.


No problems here.

The To-Do UWP app has just been updated: are you still seeing the error?


I have 1.31.1805.16001 version of to-do. Uptodate, as per Windows Store. But still have the pb. Strangely i can connect with a "live" account, but it should not be possible.

Not sure it can be related or not, but on computer it does not work, i am also connected as a "guest" to "Teams UW App" to another company. With this guest account, i do not have an Exchange mailbox i presume. I can switch in team from my main account to this space where i am just a guest.


Of course, perhaps there is not linked to . Teams works properly any way. Only To Do UW App have the pb. And on one computer only - but my main computer ((