Microsoft 365 Alert – Service Degradation – Exchange Online – Users may encounter crashes in the classic Outlook desktop app when right clicking in an email message – RESOLVED

01/07/2026 08:47:00 AM

NHS.net Connect Reference: INC46866381

Microsoft Reference: EX1409958

Issue Status: RESOLVED

Issue Description: Some users may encounter crashes in the classic Outlook desktop app when right clicking in an email message.

More info: This issue affects users on Current Channel or Monthly Enterprise Channel version 2605. While they are focused on remediation, users with access to the new Outlook desktop app or Outlook on the web may use these apps to bypass the impact. As an alternative option to more quickly self-mitigate and allow use of the classic Outlook app, users may update to version 2606, which isn’t affected by this problem.

Final Update: 02/07/2026 08:57:00 AM – Following their completed change reversion, their internal service telemetry validated that the impact has been remediated. Any user that continues to experience crashes in classic Outlook should restart their device so their changes can be applied

Scope of impact: Some users on Current Channel or Monthly Enterprise Channel version 2605 right clicking in classic Outlook desktop email messages may be impacted.

Root cause: A recent accessibility change contains a code error, resulting in impact.

Next steps: Microsoft are further analysing the offending accessibility change and the code error it introduced so they can improve our pre-deployment testing and validation processes.