Classic Outlook Copilot Buttons Vanish for Some Users, Temp Fix Available
A known issue is causing the Copilot and Copilot Chat buttons to disappear from Classic Outlook for some Windows users. Microsoft is still investigating this problem, which affects customers with a paid M365 Copilot (Premium) account or those with the Copilot Chat (Basic) license. This means that users may struggle to access these essential features in their email client.
The issue appears to be related to an upgrade to Classic Outlook for Windows, specifically after building 20026.20182 and higher is installed. According to Microsoft, the problem arises when Outlook is unable to locate a specific property within the profile section, which prevents the Copilot component from persisting in settings. As a result, the buttons may not be visible in the navigation pane.
Affected users are advised to try a temporary fix by enabling the “Show Apps in Outlook” option in Classic Outlook settings. To do this, select the File tab, go to Options, and then Advanced. Check the box for “Show Apps in Outlook” under “Outlook panes”. This should allow users to access their Copilot features through other entry points, such as the Microsoft 365 Copilot standalone app or web experience.
It’s worth noting that while this workaround is available, Microsoft has confirmed a separate bug affecting systems running Kaspersky Antivirus software. Users experiencing unexpected Outlook crashes linked to the Kaspersky Mail Checker (mcou.dll) should contact Kaspersky support for assistance. This issue is still under investigation by the Outlook Team.
This latest problem joins a growing list of issues affecting Classic Outlook, including previous bugs that rendered the client unusable when enabling Microsoft Teams Meeting Add-in and prevented users from sending emails via Outlook.com. These incidents highlight the importance of staying vigilant and up-to-date with software patches to avoid disruptions in productivity.
In light of these issues, it’s essential for businesses and individuals using Classic Outlook to prioritize software maintenance and take proactive steps to mitigate potential problems. By keeping their email client and associated applications updated, users can minimize the risk of encountering similar issues in the future.
Source: Bleeping Computer — 2026-09-16