Microsoft 365 companion apps retire by 16 December, and already get no security fixes

Microsoft 365 companion apps retire by 16 December, and already get no security fixes

22 September 2026: Microsoft will retire three Microsoft 365 companion apps for Windows 11 on 16 December 2026: Calendar, People and Files. Its retirement page, published on 17 September, says the apps will be fully retired and non-functional before that date, and may go sooner depending on when each organisation removes them.

The part that cannot wait until December

The date is in December, but the risk starts now. Microsoft's page says updates and fixes, security fixes included, are no longer being provided for the companion apps. If a problem needs a fix during the retirement period, Microsoft's answer is to uninstall the apps. In practice they are unsupported software already, on every device where they are installed.

No data is at risk from removing them. Files, calendar events and contacts live in Microsoft 365 services, not in the apps, and Microsoft says nothing is deleted by the retirement. For calendar and people information it points users to Outlook and Teams. For files, it points to Windows Search, File Explorer, SharePoint and OneDrive.

How the apps got onto your devices

Microsoft lists three routes, and each needs its own clean-up:

• Automatically, through Microsoft 365 Apps updates on eligible Windows 11 devices, unless an admin opted out. Microsoft has stopped installing them this way. But it will not clear the "Enable automatic installation of Microsoft 365 companion apps" setting in the Microsoft 365 Apps admin center, and recommends admins clear it themselves under Device Configuration, Modern App settings.
• Through Microsoft Intune or another software-distribution tool. Any Required or Available assignment for the companion apps' Win32 app entry must be deleted. Otherwise Intune reinstalls the apps after they are removed, which Microsoft lists as the usual reason they reappear.
• Directly by users. On devices the organisation does not manage, users have to remove the apps themselves.

What to do this month

• Delete the Intune assignments for the companion apps entry before you uninstall anything.
• Clear the auto-install setting in the Microsoft 365 Apps admin center.
• Uninstall from managed devices. Removing one companion app removes all three, which makes a single uninstall action enough.
• Tell users on unmanaged devices to remove them under Windows Settings, Apps, Installed apps, by searching for Microsoft 365 companions.
• Point people at the replacements before the apps disappear, so nobody loses a workflow they relied on.

Sources

• Microsoft Learn, "Microsoft 365 companion apps retirement" (updated 17 September 2026) - 17 September 2026