Outlook conflict error when updating or cancelling meetings workaround
The Outlook Team is investigating this issue. This issue is also published to the Service Health Dashboard as EX800425.
In the meantime, please use the following workarounds:
Workaround 1:
Make meeting updates in Outlook Web Access (OWA) or use new Outlook. The conflict does not occur when updating or cancelling the meeting in OWA or new Outlook. The conflict issue is only in Outlook Desktop and only on the machine that the conflict is found. It is not on other machines or on recipients’ copies of the meetings.
Workaround 2:
To mitigate the calendar conflict issue, you can use the Clear Offline Items for your calendar. These steps clear the calendar items in the Outlook store (OST) on your local machine. After performing these steps, Outlook will sync clean copies of the meeting items from the service.
These steps do not fix duplicates. Meetings that will be fixed by these steps are those indicated by a diamond.
Example:
To clear offline Calendar items, follow these steps:
- Close all Office Applications.
- Open the Calendar pane in Outlook, and right-click the Calendar folder.
- Select Properties.
- On the General tab, select Clear Offline Items.
- Select OK.
More info: https://support.microsoft.com/en-us/office/outlook-shows-conflict-errors-when-updating-or-cancelling-meetings-69c26227-40ef-4377-8f12-1749fcaad2ad