Microsoft 365 companion apps are being retired: what are they and what do you need to do?

Microsoft is retiring its Microsoft 365 companion apps Calendar, People and Files; in December 2026.

The apps will no longer work from 16 December 2026. You may lose them earlier if your IT team or Managed Service Provider (MSP) removes them ahead of Microsoft’s deadline.

For most firms, this is not a major technology change. However, it does require some action. Your IT team or MSP should establish whether the apps are installed, whether anyone is using them and how they will be removed. There is also a communication point. If people within the firm use one of these apps as part of their normal working day, they need to know that it is disappearing and what they should use instead.

What are the Microsoft 365 companion apps?

Microsoft introduced these three lightweight Windows apps in 2024-2025, with the idea that they could provide quick access to information already held within Microsoft 365 but without needing to use full Outlook:

• Calendar – provides quick access to calendar information;
• People – provides access to contacts and information about colleagues; and
• Files – helps users find recently accessed and relevant Microsoft 365 files.

The apps were available at no additional cost with certain Microsoft 365 and Office 365 plans and, on some Windows 11 devices, they were also automatically installed unless your IT team ort MSP specifically opted out. This means there may be devices within your firm where the apps are installed even if the firm did not make a deliberate decision to deploy them.

Is Microsoft removing calendars, contacts or access to files?

No. and if the loss of these apps is causing concern, this is probably the most important point to communicate to users. Microsoft is retiring the companion apps – not removing the underlying Microsoft 365 services or deleting the information accessed through them. Outlook calendars will remain available. Contacts will not be deleted. Documents will remain accessible. Users will continue to be able to access this information through the other Microsoft 365 applications and services they already use:

• For calendars and contact information, Microsoft recommends Outlook and Teams.
• Files can continue to be found through File Explorer, Windows Search, OneDrive, SharePoint and Microsoft 365 applications such as Word, Excel and PowerPoint.
• Microsoft also identifies Copilot as another way of finding files, people and calendar information where the firm has access to the relevant Copilot capabilities.

For most users, therefore, this is a change to how they access information rather than a change to the information itself.

What should your IT team or MSP do?

Microsoft has stated that organisations are responsible for removing the companion apps from devices on which they are installed.

For managed devices, this is likely to be work for your internal IT team or MSP.

They should:

1. Identify where the apps are installed. Check the firm’s Windows devices and establish whether Calendar, People or Files are present.
2. Establish whether they are being used. Identify any users or teams that rely on the apps and may need additional communication or support.
3. Stop any existing deployment. Check Intune and any other software deployment tools to make sure the apps will not simply be reinstalled after they have been removed.
4. Remove the apps from managed devices. Use the firm’s normal software management tools to carry out the removal.
5. Consider unmanaged devices. Where the firm permits devices that are not centrally managed, users may need instructions for removing the apps themselves.
6. Communicate with affected users. Explain what is being removed, when it will happen and, importantly, that their underlying files, contacts and calendar information are not being deleted.
7. Explain the alternatives. Make sure users know where they should go to perform the same tasks using Outlook, Teams, OneDrive, SharePoint, File Explorer or other Microsoft 365 applications.
8. Check that the work has been completed. Monitor the removal and investigate devices where the uninstall has failed or has not taken place.

There is little benefit in leaving this until Microsoft’s December deadline. Dealing with it earlier will give the firm time to identify anyone who relies on the apps, communicate the change properly and resolve any technical (and training) issues before the applications stop working.

Don’t assume your MSP has it covered

If your firm outsources its IT, it would be reasonable to expect your MSP to deal with the technical aspects of this change, but that does not mean the firm should simply assume it is happening. Ask your MSP whether the companion apps are installed within your environment, whether they are being used and what the plan is for removing them. The MSP may carry out the technical work, but you as a business still needs to understand whether your people will be affected and whether any communication or training is required. This does not need to become a lengthy project. In many firms, the answer may simply be that the apps are installed on a small number of devices, nobody uses them and they can be removed centrally, but the important thing is to know that rather than assume it.