Conflict in Tasks

Copper Contributor

I work on a .Net WinForm based PracticeManagement software. Users can create tasks in the application which are then pushed to Outlook. 


Beginning 17-Aug-2021 we are seeing sync issues in Outlook Tasks. Occasionally tasks are being marked conflicted in Task view and when user tries to do any thing with the task or if my application tries to read the task then it throws the error "One or more items in the folder you synchronized do not match. To resolve the conflicts, open the items, and then try this operation again."


Double clicking on the item opens up a Conflict Message dialog which shows 1 or 2 versions of the tasks and asks user to choose which one to keep.


My query is:

  1. why is Outlook flagging of tasks as conflicted when no change to the task was made by either user in Outlook or by my PraticeManagement application.
  2. This issue never occurred before and why suddenly this has started. Has anything changed in Microsoft 365 e-mail servers.

As of now we have tried to get users to resolve the conflict manually, re-create the Outlook profiles, but the issue keeps re-occurring.


Any help will be greatly appreciated. I have attached some screenshots for reference.

5 Replies


We are having this same problem, did you ever find a fix?





Hi George, we have found doing an Office repair (quick fix) seems to resolve the issue. We are not sure this is the solution but users haven't come back with this problem after repair. So give it a shot.




Hi Arun,


Thanks so much for getting back to me.  I will try this over the weekend.


Have a blessed day!





We're having the same problem. Trying Arun suggestion "quick repair"

but problem still exist. Do you have any solution to fix this problem?







Hi John,


Our IT guy has been trying to come up with a fix for this with no luck yet.  If we find one I will reach out and let you know.  Very frustrating for sure.