Canada time zone: Microsoft's Exchange fix skips recurring meetings

Most of British Columbia, Alberta and Manitoba left their clocks alone on November 1 instead of falling back, and Microsoft's software is still catching up. The provinces now sit year-round on UTC-7, UTC-6 and UTC-5. Microsoft's guidance, KB 5134344, went up on October 26, six days before the change, and was last updated on November 2. Its summary lists eight products with confirmed problems: the Outlook and Exchange Online calendar, Teams Rooms on Windows, SharePoint on-premises, the Teams Auto Attendant, Power Automate, Fabric, Bookings and Dynamics 365 Finance and Operations. Its detailed table adds Teams Events, Azure Automation and Power Pages. Teams on desktop, web and mobile and Outlook for iOS, Android and Mac are still being checked.

For a company with staff or customers in those provinces, the symptom is meetings an hour out, and automated jobs running at the wrong time. Manitoba's government names "Microsoft 365, Google Workspace and other calendars" among the systems to check.

What has shipped and what hasn't

Microsoft lists the Windows updates as released for Windows 11, Windows 10 Enterprise LTSC 2021 and Windows Server 2016 through 2025; the new Manitoba zone came in the October 13 security update. Devices on unsupported versions of Windows won't receive the update. Microsoft says Bookings updates are out too, though the University of Victoria still saw booking errors on October 28.

The Exchange Online tool is a PowerShell cmdlet, Invoke-CalendarEventMigration, which Microsoft has documented; KB 5134344 gives November 4 as its release date, and Message Center post MC1526468 first gave October 28, a week earlier. The first version moves single meetings and appointments only, and only those the mailbox organizes, in its default calendar. Every moved meeting sends an update to its attendees. The fix for recurring meetings has no date. Microsoft is still investigating free/busy and working-hours display in the web and new versions of Outlook.

Elsewhere, the SharePoint on-premises update is due November 10. Power Pages, which can show server-formatted dates an hour off, has a December 12 milestone. Azure Automation has no date.

The stand-in time zones

Until the new zones work everywhere, Microsoft tells admins to pick an existing zone with the right offset and no daylight saving:

Microsoft says not to use the new Alberta, British Columbia or Manitoba zone IDs in Power Automate yet, and calls these mappings temporary. In Fabric, set the zone in the schedule itself; device settings are not enough.

What admins are running into

The Register quoted a sysadmin on Reddit who called Microsoft's guidance "terrible" and said he had written roughly 900 lines of PowerShell to fix calendars. The University of Victoria's IT team found that a bug in the new B.C. zone broke free/busy, so it set working hours to Yukon; staff on classic Outlook must switch to new Outlook or set Windows to Yukon, which leaves items from November 2, 2025 to March 8, 2026 an hour off. Recurring meetings with no end date could not have their zone changed. And because every attendee gets an update email, staff updating meetings with many attendees ran into sending limits, so the university raised them to 2,000 messages a day until November 6.

In Outlook, only the organizer can change the time zone of a meeting with attendees, and changing a recurring series wipes the changes made to single occurrences, which then have to be redone. Outlook for Mac needs build 16.114.26102345 or later to see the new zones, and may still show B.C. as UTC-08:00.

Related: October Windows updates stall Exchange mail and Microsoft's October 13 end-of-support list.