Users may experience an error when updating a meeting in their own or a shared calendar

Last Updated: February 5, 2026

ISSUE

When a user updates a meeting in their own calendar or a shared calendar, they may experience one or more of the following errors:

"The function cannot be performed because the message has been changed”

“The item cannot be saved because it was changed by another user or in another window”

"The operation cannot be performed because the message has been changed”

"The operation cannot be performed because the object has been deleted”

STATUS: INVESTIGATING

The Outlook team is investigating this issue. There are reports of such errors through specific workflows connected with service Event Based Assistant routines. We do not have an ETA for a potential fix and will update this topic when we know more. For those that have support cases open, or if you are opening a case, please collect the logs referenced below and share them with your support engineer.

This issue can be avoided or resolved by adjusting the profile setup or changing the speed of updates that you make:

Wait 1-2 minutes before making changes to calendar events that you just sent out. If you send a meeting invite and then immediately need to add another user, for example, allow a minute for the meeting to sync to the server before sending another update to the meeting. If you get one of the errors referenced dismiss the error message and proceed with saving your changes.
Increase the time before messages are autosaved as explained in the workaround in this article, The operation cannot be performed because the message has been changed error when a delegate creates a Skype or Teams meeting in Outlook. If Event Based Assistants (EBAs) are making changes to the meeting item before you send it then it will cause a message that the meeting has been changed. To avoid this problem, you can increase the autosave to be longer if you need time to edit meeting items. You may need to experiment with how much time you need before the autosave and possible EBA edits to your item.