Microsoft 365 Alert – Service Degradation – Exchange Online – Users may see that after selecting a meeting room when scheduling meetings, it changes from available to unavailable – ONGOING

19/03/2026 09:25:00 AM

NHSmail Reference: INC46777325

Microsoft Reference: EX1233142

Issue Status: ONGOING

Issue Description: Users may see that after selecting a meeting room when scheduling meetings, it changes from available to unavailable.

More info: While we are working to remediate the impact, admins can mitigate the issue by assigning the desired working hours and the time zone for the meeting rooms.

Current Update: 29/05/2026 09:51:00 AM –Microsoft are progressing with their internal tests and validations so they can ensure their deployment remediates the impact. Their fix deployment timeline projects that the deployment will have completed by Friday, June 19, 2026, and they are assessing options to expedite its release, which they anticipate they will have further clarity on by their next scheduled communications update.

Scope of impact: Any users that are trying to select a meeting room when scheduling meetings outside the room’s working hours in Exchange Online may be impacted. This information may be updated as our investigation continues.

Root cause: A recent expansion of the feature logic used to book rooms for scheduled meetings contains a code complication which automatically sets the meeting rooms’ default working hours to appear in Pacific Standard Time instead of their accurate time zone.

Next update by: Wednesday, June 10, 2026, at 10:00 PM UTC