i have a Office 365 exchange account, issue with Outlook desktop syncing tasks.

Question

Just set up an Office 365 Business standard account with exchange. I had been using POP email, and have a MS to do app that I use. I now can get the desktop and browser to do syncing. and it syced once with outlook. I deleted several tasks and lists from the browser and app. The deletion did not sync into outlook tasks however, they still show in tasks in outlook.
I have deleted the OST file and allowed it to repopulate, no change. Started and restarted outlook, no change.

I am signed into the same account on the to do app and the browser and outlook.

Any suggestions on how to have outlook tasks sync correctly and delete tasks deleted in the browser?

Win 11 64 bit pro.

Answer 1

I changed a task in the desktop to do app and suddenly outlook was syncing just fine. No idea why it started working, but it is working fine now.

Answer 2

Dear @RLTidd72,

Good day. Thank you for posting your question in the Microsoft Q&A forum!

First of all, I’m sorry you’re having a problem and for the situation you encountered, I deeply understand the inconvenience caused and apologize for it.

For better assist, please kindly let me know some information:

• Are you currently using classic Outlook for Windows or the new Outlook experience?
• When you delete a task in the Microsoft To Do web https://to-do.office.com, does the task remain deleted there after a refresh, or does it reappear?
• Do the same tasks still appear in Outlook on the web under Tasks, or is the issue only present in the Outlook desktop client?
• Were these tasks originally created in Outlook when the account was still configured as POP, or were they created directly in Microsoft To Do?
• Additionally, please go to File > Account Settings > Data Files and share a screenshot of the data files listed there.

Note: Please note that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. 

Your patience and understanding are highly appreciated. I am looking forward to your response!

Answer 3

You should be able to fix this by installing the most recent updates for Windows 11. See https://support.microsoft.com/en-us/office/classic-outlook-profiles-with-pop-accounts-and-psts-hang-after-windows-updates-on-january-13-2026-590fe356-ecc2-49f4-b9e3-bd39fafa58f6 .