Microsoft 365 Alert – Service Degradation – Exchange Online – Users may be unable to view or update the body of some recurring calendar events in multiple connection methods – RESOLVED

28/02/2025 08:25:00 AM

NHSmail Reference: INC46463747

Microsoft Reference: EX1017243

Issue Status: RESOLVED

Issue Description: Users may be unable to view or update the body of some recurring calendar events in multiple connection methods.

More Info: This event specifically impacted users attempting to view or update the body of calendar events that were an exception in a series. An exception in this case was defined as a calendar event that was edited to an alternate time from when the recurring meeting typically meets.

Some users may have seen various additional symptoms if they were leveraging automations or third-party apps that rely on the presence of message body content.

This event impacted all Outlook clients excluding the classic Outlook desktop client.

Final Update: 28/02/2025 08:25:00 AM – Microsoft have confirmed with affected users that reverting the offending service update has remediated the impact.

Scope of impact: Some users attempting to view or update the body of recurring calendar events that were exceptions in a series in the new Outlook desktop client, Outlook on the web, or Outlook mobile may have been affected.

Root cause: A recent service update that intended to improve the functionality of the calendar event body read/write process contains a code issue, resulting in impact.

Next steps: Microsoft are reviewing our feature update testing and validation methods to better identify the potential for impact to calendar events prior to deployment to prevent similar impact in the future, and to improve their pre-deployment update testing processes.