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Lack of Usefulness Condemns Microsoft 365 Companion Apps
When Microsoft launched the Microsoft 365 companion apps in November 2025, I asked why the apps existed at all. Separate apps to interact with Calendar, Files, and People data just didn’t make sense in the context of Microsoft 365 where people use integrated apps such as Outlook classic and the much-commented-upon new Outlook to take care of calendar and people. Files can be handled using anything from Windows Explorer to Microsoft Copilot.
After I made my comments about the companion apps, the developers said that they had great plans to address the obvious gaps in functionality and usefulness exposed by the initial release. Alas, nothing much ever happened except the inevitable, and Microsoft drew a line under the companion apps by announcing their retirement in message center notification MC1474111 (18 September 2026).
The Great Cleanup Begins
The companion apps will cease working on December 16, 2026. Administrators might not be aware that Microsoft installed the apps on PCs along with updates for the Microsoft 365 apps (subscription version of Office), or that the apps launched automatically unless they were explicitly instructed not to through app settings. Think of it as an example of bloatware thoughtfully brought to Microsoft 365 customers without their knowledge or desire.
If you want, you can leave the defunct apps alone and they’ll do no harm apart from occupying some disk. No automatic cleanup of the apps will happen. According to Microsoft’s guidance for the retirement, administrators and end users will have to clean up the mess left by the retirement by removing the apps from PCs. On unmanaged PCs, users can uninstall any of the apps to remove the three (Figure 1).
The Simple Fact of Limited Engineering Budgets
I never understood what business case was argued to justify the engineering cost to create and support the Microsoft 365 companion apps. Statements that the Files app was a quicker way to find files of interest just didn’t land when it is obvious that Microsoft Copilot is a superior finder of elusive files. Looking up individuals through a separate app, albeit one that didn’t take up too much screen space is not a compelling proposition. And the Calendar was a pale imitation of the full calendar functionality available in any Outlook client (or the Teams calendar).
Adding extra ways to interact with Microsoft 365 data was just confusing. It’s not as if the apps delivered any breakthrough functionality that Microsoft could bring through into mainline products after being proved in the Calendar, People, or Files apps.
The simple fact is that it’s becoming increasingly difficult to secure funding within Microsoft for projects like the companion apps that created no revenue and therefore had zero impact on the bottom line. In addition, the apps didn’t support Microsoft’s AI initiative. In short, there was no obvious value to customers or Microsoft, so a rapid cancellation is about all that the apps could expect.
No Wrong Message
Some will argue that the cancellation sends the wrong message. Don’t try something different. Focus on the bottom line and above all, support the AI initiative. To me the decision isn’t about suppressing innovation or discouraging Microsoft engineers from trying something new. The reality is that the companion apps had no place to land in the Microsoft 365 ecosystem. The apps didn’t fill a functionality gap and confused customers. I don’t think any software that confuses its potential users has much chance of success.
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