Microsoft fixes bug behind random Office 365 deactivation errors

​Microsoft has rolled out a fix for a known issue that causes random "Product Deactivated" errors for customers using Microsoft 365 Office apps.

User reports on Microsoft's community website, Reddit, and other online platforms show that affected users receive "Product Deactivated" warnings in Office apps. As the company explained when it acknowledged the bug on Thursday, the errors are triggered by licensing changes initiated by administrators.

The known issue arises when switching subscriptions from Office 365 E3 to Microsoft 365 E3 or when users are moved between licensing groups, including Azure Active Directory or synced on-premises security groups.

It can also be triggered by admins adjusting license or service plan settings, removing and re-adding users to license groups, or toggling the "Latest version of Desktop Apps" service plan under the Microsoft 365 subscription.

Over the weekend, Microsoft said the bug causing these deactivation warnings has now been addressed.

"The engineering team has deployed a patch on the service side to resolve unexpected product deactivations," the company stated in an updated support document.

​Microsoft also provides several temporary workarounds for affected customers who haven't yet received the fix, asking them to click the "Reactivate" button on the error banner and sign in when prompted. Alternatively, they can sign out of all Microsoft 365 apps, close them, and restart them before signing back in to address the deactivation issue.

If the errors persist, users are advised to ask their administrators to check the Microsoft 365 subscription management portal and see if their subscription has expired.

​For further troubleshooting, affected users are also prompted to provide the logs stored in the %temp%/diagnostics directory to support engineers.

In recent months, Microsoft has also shared a temporary fix for a known issue with Microsoft 365, causing the classic Outlook to hang or freeze when copying text, and fixed another bug that crashed Microsoft 365 apps (i.e., Outlook, Word, Excel, OneNote) when typing or spell-checking a text.