Microsoft Office 2016 and 2019 Lose Activation After KB5002907

⚡ The Gist in 5 Seconds - Summary: after installing the optional update KB5002907, Windows 11 users lose activation of licensed Microsoft Office 2016 and 2019. - Where available: the patch was distributed via Windows Update for Microsoft 365 apps that had not been updated for more than 90 days and were on Current Channel or Monthly Enterprise Channel. - Limitation: Microsoft has paused distribution of the update; in some cases, reactivation or reinstalling Office must be done manually. ### 🔍 What Was Found On September 28, 2026, it became known that Windows 11 users faced loss of activation of installed licensed copies of Microsoft Office 2016 and 2019. The problem was linked to the optional update KB5002907, intended for local files of apps tied to Microsoft 365 cloud services. The update was supposed to resume the Microsoft 365 update procedure that had not been receiving patches automatically, but instead it deactivated "perpetual licenses" in home and small business editions. According to Christian Van Houtte, owner of the company Solid Systems, five unrelated organizations approached him with complaints about suddenly losing their Office 2016 and 2019 licenses. Re-entering the key and reactivating the product helped resolve the issue. However, in some cases, installing KB5002907 resulted in the complete removal of the installed copy of Office from the disk. This happens when components of different architectures are mixed — for example, 64-bit Microsoft Access Runtime and 32-bit versions of Office 2016 and 2019. The Office installer first removes all components and then cannot restore them due to the prohibition on mixing 32- and 64-bit parts. ### 💡 Why It Matters Office 2016 and 2019 are among the programs most crucial to Russians, and a sudden loss of activation means losing access to all features of the office suite. The problem affects precisely "perpetual licenses" that users purchased for permanent use, not via subscription. Although Microsoft has already paused distribution of KB5002907, those who managed to install the patch are advised to check their activation status. In most cases, re-entering the key helps; if Office was partially removed, you will need to download the distribution again and install the package manually. Those with systems that have both 32- and 64-bit Office components should be especially careful. ### 🧩 Context KB5002907 was conceived as a tool for "healing" Microsoft 365 apps that had long gone without updates, but in practice it became the source of the failure itself. Microsoft acknowledged the problem and temporarily stopped distributing the update, but the company has not yet provided an official explanation of why the installer removes Office files. Meanwhile, the bug is being actively discussed on Reddit and the official Microsoft forum. Users who have already encountered the issue are left with either restoring activation with a key or reinstalling the office suite from scratch.

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