Security1 publisher2 min readPublished
Microsoft tells admins to uninstall the three companion apps it auto-installed a year ago
Calendar, People and Files stop working on December 16, 2026, and Microsoft has already stopped shipping them, leaving a removal job on fleets that took the apps automatically at the end of 2025.
The Watch · Security desk
What happened
- Microsoft says the Calendar, People and Files Microsoft 365 companion apps reach end of life on December 16, 2026, after which they will stop functioning and lose support.
- Microsoft stopped shipping the apps through Microsoft 365 Apps updates on Friday and told admins to remove them from tenant devices, with users of unmanaged devices asked to uninstall them.
- The same Friday bulletin told admins to move Entra ID users to passkeys, QR code authentication or FIDO2 keys before SMS first-factor sign-in retires starting in February 2027.
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Why it matters
- cost Every endpoint that accepted the default install needs a removal action before December 16, and the work produces no security improvement, only helpdesk and packaging hours.
- decision The cleanup lands on the admins who never set the Apps Admin Center opt-out in 2025; tenants that configured it have nothing to undo.
- exposure Uninstalled copies remain unsupported software in the logon startup path, so audit and inventory reviews into 2027 will keep flagging Copilot-linked apps no one is maintaining.
- precedent Default-on installation followed by an admin-executed removal eleven months later sets the expectation for the next Copilot-adjacent app Microsoft pushes to managed fleets.
The apps arrived by default. Microsoft said in October 2025 that it would install Calendar, People and Files automatically on Windows 11 enterprise devices already running the Microsoft 365 desktop client apps, with the rollout finishing by the end of December 2025 [2]. Admins could decline. The opt-out sat in Device Configuration settings in the Apps Admin Center [5]. Anyone who left the default in place owns the removal now.
All three sit in the Windows 11 taskbar and use Copilot for contextual assistance, finding people in the organisation, reaching Microsoft 365 and locally stored files, and managing the Microsoft 365 calendar [4]. Once installed, each launched at startup by default, and a user could switch that off per app with the "Start app minimized when you log in" setting [6].
"We are retiring the companion apps, and they will no longer function or be supported after 16. December 2026. We advise admins remove the apps from devices in their tenant by this date," Microsoft said in a Microsoft 365 message center update on Friday [3].
Devices that took the apps at the tail end of that rollout got about eleven and a half months of supported life out of them [9]. Microsoft stopped installing them through Microsoft 365 Apps updates on Friday, so no new copies land [7]. The copies already deployed stay until someone takes them off. For unmanaged devices, Microsoft asked admins and users to uninstall the apps themselves [8].
Treat this as inventory work. No CVE is attached, and nothing here is exploitable. The apps stop functioning on the date. What remains after December 16 is unsupported software in the logon startup path on every endpoint that received it, and it will keep showing up in asset scans until it is removed [1].
The deadline in the same Friday bulletin with real breakage behind it is the other one. Microsoft reminded admins to move Entra ID users to phishing-resistant methods, naming passkeys, QR code authentication and FIDO2 security keys, to avoid sign-in disruption when SMS first-factor sign-in retires starting February 2027 [10]. Removing three taskbar apps is a package uninstall, while re-enrolling a workforce onto passkeys takes planning, and that clock starts about two months after December 16, 2026 [11].
What to watch
- Whether Microsoft publishes a supported bulk removal path before December 16 or leaves admins to script the uninstall per device.
- Whether the Copilot lookup, file search and calendar features reappear inside another default-installed Windows 11 or Microsoft 365 component.
- Any slip in the February 2027 start date for retiring SMS first-factor sign-in in Entra ID.