Microsoft 365 Alert – Service Degradation – Microsoft Teams – Some users may be unable to open Microsoft Teams – RESOLVED

Announcements Arpan Das

27/10/2025 08:42:00 AM

NHSmail Reference: INC46665421

Microsoft Reference: TM1178840

Issue Status: RESOLVED

Issue Description: Users may be unable to open Microsoft Teams.

More info: Users who have characters in their user profile path that cannot be expressed in the Application and Network Seamlessly Integrated (ANSI) code page may be unable to open Microsoft Teams.

As a workaround, users may be able to open Microsoft Teams using Microsoft Teams on the web.

Final Update: 30/10/2025 08:20:00 AM – After an extended period of monitoring the affected portion of the environment following the deployment of our fix, Microsoft have confirmed that impact has been remediated.

Scope of impact: Your organization is affected by this event, and some users attempting to open Microsoft Teams who have characters in their user profile path that cannot be expressed in the ANSI code page may be impacted.

Root cause: A recently merged code change introduced a code issue, resulting in impact.

Next steps: Microsoft are review their code merging validation process to identify possible refinement in order to prevent similar instances of this issue in the future.