Copilot buttons missing in classic Outlook for Windows remain unresolved, with Microsoft confirming it is still actively investigating the fault while offering a temporary workaround for affected users.
The problem surfaces for customers holding either a Copilot Chat (Basic) licence or a paid M365 Copilot (Premium) account. For those users, the Copilot and Copilot Chat buttons can simply vanish from the side navigation pane and the area above the ribbon, with no obvious reason why.
What the Copilot Buttons Missing in Outlook Bug Actually Does
Microsoft has laid out the ways the fault can present itself. The Copilot button may disappear from the top-right area above the ribbon entirely. The Copilot icon can go missing from the left app bar or the More Apps section. Opening Copilot through the Add Apps menu may appear to do nothing at all when a user selects it. Attempting to add Copilot via ribbon customisation can leave the command greyed out and unavailable.
In its most recent update on the matter, Microsoft pinpointed the trigger: upgrading classic Outlook for Windows to build 20026.20182 or higher. The technical explanation is unusually specific. ‘The Outlook Team is actively investigating this issue. Current analysis indicates that, in affected environments, Outlook is unable to locate the MAPI property PR_PROFILE_USER_SMTP_EMAIL_ADDRESS_W within the null profile section,’ Microsoft stated. ‘As a result, the Outlook Copilot component cannot persist in Copilot-related settings, which may prevent the Copilot entry point from appearing in the Outlook navigation pane.’
In plain terms: a missing profile property stops the Copilot component from saving its settings, so it never bothers to show up. It is a plumbing problem rather than a licensing one, which will be cold comfort for anyone who has just paid for a premium Copilot subscription.
Workarounds While Microsoft Works on a Permanent Fix
Microsoft has shared a few options for users who cannot wait. The most straightforward is enabling the ‘Show Apps in Outlook’ toggle buried in the classic Outlook settings: go to File, then Options, then Advanced, and tick the box labelled ‘Show Apps in Outlook’ under the ‘Outlook panes’ section. It is not elegant, but Microsoft says it should restore the missing entry points.
Creating an entirely new Outlook profile is a second route around the fault. Alternatively, users can sidestep classic Outlook altogether: the new Outlook client, Outlook on the web, and the Microsoft 365 Copilot standalone app are all unaffected by the bug and continue to surface Copilot normally.
The Copilot disappearing act is not the only issue Microsoft is juggling in classic Outlook right now. The company has separately confirmed a bug causing unexpected Outlook crashes on machines running Kaspersky Antivirus software. Those crashes generate ‘Event 1000’ entries in the Windows Application log, tied to the Kaspersky Mail Checker component (mcou.dll). The Outlook Team is investigating that one too, and in the meantime has directed Kaspersky users experiencing crashes to contact Kaspersky support directly.
Earlier this year, Microsoft resolved a separate pair of classic Outlook problems: one that rendered the client unusable when the Microsoft Teams Meeting Add-in was enabled, and another that blocked certain users from sending emails via Outlook.com. The current MAPI-related fault joins a queue that, it is fair to say, has been keeping the Outlook engineering team busy.
Microsoft has not given a timeline for a permanent fix to the Copilot buttons missing in Outlook issue, so the workarounds above are currently the only options on the table for affected users.
