Conflict Message Error when trying to Open a Meeting Invite

Here are the steps to clear offline items. Keep in mind this will remove all the calendar items from your local copy of your calendar. After you do this step, you can restart Outlook and it will start syncing the calendar again from the service and pull down a clean copy with no conflicts.

To clear offline Calendar items, follow these steps: 

1. Close all Office Applications.
2. Open the Calendarpane in Outlook, and right-click the Calendarfolder.
3. Select Properties.
4. On the Generaltab, select Clear Offline Items.
5. Select OK.

The fix is deployed from the service and no changes are needed from the client or the user to get the fix. The fix will prevent any new occurrences of the issue.

If you have users that have calendar conflicts with the diamond indicator on the meeting then they still need to do Clear Offline Items, New OST, or new Outlook Profile to clean those up.

If users have duplicated meetings because they clicked Keep All on the Conflict Message dialog that can be mitigated using Calcheck. When you use Calcheck you have to edit a config file to tell it what items to move off the calendar. Its important to make sure users edit the calcheck.cfg file. I am updating the Known Issue with a sample calcheck.cfg file you can use or reference instead.

The mitigations are listed in the Known Issue and has pending updates that will go live shortly, Outlook shows conflict errors when updating or cancelling meetings - Microsoft Support.

how can I Clear Offline Items?

The fix is deployed from the service and no changes are needed from the client or the user to get the fix. The fix will prevent any new occurrences of the issue.

If you have users that have calendar conflicts with the diamond indicator on the meeting then they still need to do Clear Offline Items, New OST, or new Outlook Profile to clean those up.

If users have duplicated meetings because they clicked Keep All on the Conflict Message dialog that can be mitigated using Calcheck. When you use Calcheck you have to edit a config file to tell it what items to move off the calendar. Its important to make sure users edit the calcheck.cfg file. I am updating the Known Issue with a sample calcheck.cfg file you can use or reference instead.

The mitigations are listed in the Known Issue and has pending updates that will go live shortly, Outlook shows conflict errors when updating or cancelling meetings - Microsoft Support.

I am facing the same issue from last month and getting reminder for a meeting which happened almost a month ago. Conflict error is very annoying and every time when you click on a mail related to the invite like accept or denied from someone, it says, this meeting is not available or deleted in your calendar. Please resolve this quickly.

Can you confirm if the fix is applied automatically or is there something we need to do on our end?

We have users still reporting the issue so please confirm without copying your previous message. Thank you.