Classic Outlook bug breaks Copilot, but some might call it an upgrade

Developer August 14, 2026No Comments

When does a bug become a feature? Microsoft needs to answer that question now that classic Outlook may hide the Copilot button and stop other Copilot features from working.

A bug that appears with build 20026.20182 of classic Outlook prevents access to Copilot Chat and removes Copilot entry points within the app.

“After classic Outlook for Windows updates to build 20026.20182 and higher, you no longer have Copilot Chat or Copilot entry points in Outlook,” reads a Microsoft support document. “This issue happens if you have a Copilot Chat (Basic) license or a paid M365 Copilot (Premium) account.”

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While it’s easy to joke about Copilot going missing being “addition by subtraction,” the bug is likely frustrating for those that rely on Copilot within classic Outlook.

If your system is affected by the bug, the Copilot button could be missing from the top-right area above the ribbon. The Copilot icon can also go missing in the left app bar or the More Apps area.

Even if you see the Copilot icon in the Add Apps section, selecting “Open” may not do anything at all. Even if you’ve added Copilot through ribbon customization, the option may appear grayed out or unavailable.

Only classic Outlook is affected, meaning Copilot still appears and works as usual within the web version of Outlook and other versions. The Microsoft 365 Copilot app and web experience are also working normally, though it’s worth noting Microsoft has a new unified Copilot experience rolling out.

If you need to use Copilot immediately, Microsoft suggests switching to Outlook on the web or the new Outlook app. While standard fixes like creating a new Outlook profile, clearing local cache data, re-signing into Office, or restarting Windows have been tried, Microsoft notes they don’t consistently restore the missing buttons.