Microsoft has addressed a long-standing problem in which Copilot Chat and Copilot buttons disappeared from the classic Outlook desktop application on Windows systems. According to an updated support document, users holding either a Copilot Chat (Basic) license or a Microsoft 365 Copilot (Premium) subscription were unable to see Copilot interface elements in the side navigation or above the ribbon.

The bug manifested in several ways for affected users:

  • Copilot button absent from the top-right position above the ribbon
  • Copilot icon not appearing in the left app bar or More Apps section within classic Outlook
  • Copilot listed as available in Add Apps, but the Open action produced no result
  • Ribbon customization showing Copilot as unavailable or grayed out
  • Copilot remaining accessible through alternative channels such as Outlook on the web, the standalone Microsoft Copilot app, or web interface

The company initially announced a fix in June through a service update, but the problem reappeared after subsequent updates were deployed. Microsoft subsequently commenced another investigation to address the recurring issue.

The underlying cause stemmed from a defect that blocked Outlook from accessing certain account details stored in the user's Outlook profile. Microsoft explained the resolution in an updated support article:

We fixed an issue in classic Outlook that could cause the Copilot entry point to be missing from the navigation pane when required account information could not be retrieved from the user's Outlook profile. The Copilot button might be missing for several different reasons, including licensing, Microsoft 365 app configuration, update channel, privacy settings, or other environmental factors.

Microsoft support document

Microsoft advised users to consult Copilot troubleshooters and documentation titled "How to find and enable missing Copilot button in Microsoft 365 apps" to diagnose and resolve the underlying cause, since the missing button can result from multiple factors.

For users still experiencing the problem, Microsoft provided a temporary workaround. Users can enable the "Show Apps in Outlook" option by navigating to File > Options > Advanced in classic Outlook settings and checking the "Show Apps in Outlook" box under the "Outlook panes" section.

Alternatively, affected users may switch to the new Outlook email client or Outlook Web Access (OWA), neither of which are impacted by this bug, or establish a fresh Outlook profile.

This resolution follows other fixes Microsoft has implemented for classic Outlook since the beginning of the year, including corrections for issues that blocked some users from sending emails through Outlook.com and a problem that rendered the classic Outlook client inoperable when the Microsoft Teams Meeting Add-in was activated.