Microsoft Still Investigating Copilot Button Disappearance Bug
Microsoft is still investigating an issue affecting some Windows users who are unable to see the Copilot and Copilot Chat buttons in Classic Outlook. This problem was first acknowledged by Microsoft in June when it announced a fix via a service change.
The affected customers have either a Copilot Chat (Basic) license or a paid M365 Copilot (Premium) account, which may cause the Copilot buttons to disappear from the side navigation and above the ribbon. Users experiencing this issue may also encounter one or more of the following problems:
The Copilot button is missing from the top-right area above the ribbon.
The Copilot icon is missing from the left app bar or More Apps area in classic Outlook.
In Add Apps, Copilot may appear as an available app, but selecting Open does nothing.
Adding Copilot through ribbon customization may show the command as unavailable or grayed out.
However, users can still access Copilot from other entry points, such as Outlook on the web or the Microsoft 365 Copilot standalone app or web experience.
A temporary workaround has been shared by Microsoft to enable the 'Show Apps in Outlook' option in classic Outlook settings. This requires going to the File tab, then Options, and Advanced, where users can check the box for 'Show Apps in Outlook' under 'Outlook panes'. Additionally, creating a new Outlook profile or using the new Outlook email client or Outlook Web Access (OWA) are also viable solutions.
Microsoft is still investigating this issue, which occurs after upgrading classic Outlook for Windows to build 20026.20182 and higher. The company has confirmed that it's working on a permanent fix but in the meantime, affected users can try these workarounds.