Copilot Button Missing in Classic Outlook: How to Get It Back

You open classic Outlook and the Copilot button above the ribbon is gone. Or you click the app bar on the left side and the Copilot icon which used to sit there isn't showing anymore. It's not your license, and it's not a setting you accidentally changed.

This started showing up widely in the second week of September 2026, and Microsoft's support team confirmed it on their known issues page a few days later. I checked three affected machines on our team this week, two paid M365 Copilot seats and one Copilot Chat Basic account, and the symptom looked identical on all three: the button isn't there at all. Here's what's causing it and the two fixes to bring it back.

Why Did the Copilot Button Disappear From Classic Outlook?

Microsoft confirmed the cause on its known issues page, last updated September 15, 2026: classic Outlook for Windows on build 20026.20182 and higher fails to locate a specific profile property it needs to keep Copilot's settings in place. The Copilot entry point then never loads into the ribbon or navigation pane.

The property is called PR_PROFILE_USER_SMTP_EMAIL_ADDRESS_W. Outlook stores Copilot-related settings inside a section of your mail profile, and on affected builds this section comes up empty, described by Microsoft as a "null profile section." Without it, the Copilot component has nowhere to save its state, so it never draws its button. This is a Microsoft-side bug, not something you broke by changing a setting. It hits both Copilot Chat (Basic) users and people paying for M365 Copilot (Premium).

You'll recognize it by one or more of these:

• The Copilot button above the ribbon is gone entirely
• The Copilot icon is missing from the left app bar or the More Apps section
• Copilot still shows up when you check Add Apps, but clicking it does nothing
• Ribbon customization options related to Copilot are greyed out

Status as of today: Microsoft lists the issue as "Investigating," with no permanent fix shipped yet. This means the workarounds below are what you have to work with right now.

How Do You Check If Your Outlook Build Is Affected?

Open File, then Office Account, and look at the version number under "About Outlook." If it reads 20026.20182 or higher on the Current Channel, you're on a build where this bug shows up.

1. Click File in the top-left corner of Outlook
2. Select Office Account from the left sidebar
3. Click About Outlook
4. Read the version and build number in the popup window

If your build number is lower than 20026.20182, the Copilot button disappearing is likely a different problem, and you should check your Copilot license status in the Microsoft 365 admin center or your personal account settings instead.

What's the Official Workaround for the Missing Copilot Button?

Microsoft's published fix is to turn on the "Show Apps in Outlook" setting, which forces the app bar to render again and brings the Copilot icon back with it. This takes under a minute and doesn't require a restart in most cases, though closing and reopening Outlook afterward helps if the icon still doesn't appear right away.

1. Click File, then select Options
2. Go to the Advanced section in the left sidebar
3. Scroll down to Outlook panes
4. Check the box next to Show Apps in Outlook
5. Click OK and restart Outlook if the Copilot icon doesn't show up immediately

This setting controls whether the app bar (the vertical strip of icons on the left edge of Outlook) displays at all. On affected builds, this bar sometimes collapses along with the missing profile section, taking Copilot down with it. Turning the setting back on rebuilds the bar and, for most people affected, restores the icon.

What If Show Apps in Outlook Doesn't Bring It Back?

If the checkbox fix doesn't work for you, the next most reliable option is creating a fresh Outlook profile, since it forces Outlook to rebuild the broken profile section from scratch instead of trying to repair the existing one.

1. Close Outlook completely
2. Open Control Panel and search for Mail
3. Click Show Profiles
4. Click Add, name the new profile, and follow the prompts to add your account
5. Set the new profile as your default under Always use this profile
6. Open Outlook and confirm it loads the new profile

This rebuilds the profile data from scratch, including the section where the missing MAPI property lives. It takes longer than the Show Apps toggle, usually five to ten minutes depending on how much mail syncs back down, but it fixes cases where the app bar setting alone doesn't help.

A second option: if your organization manages Office updates through Group Policy or the Office Deployment Tool, IT staff have the ability to pin the Current Channel back to build 16.0.20026.20168, the last version before this bug shipped. For a home user on a personal PC, this means going to Control Panel, then Programs and Features, right-clicking Microsoft 365, and choosing Change, then Online Repair won't roll back the version. Reverting a specific build number requires the Office Deployment Tool, which is a heavier fix best left to IT-managed machines rather than a personal laptop.

Is Copilot Still Usable While the Button Is Broken?

Yes. Your license and credits stay untouched, so switching to a different Copilot entry point gets you back to work immediately without waiting on Microsoft's fix.

• Outlook on the web: sign in at outlook.office.com, where Copilot runs independently of the classic desktop app and isn't affected by this bug
• Microsoft 365 Copilot app: the standalone app (or its web version at m365.cloud.microsoft) gives you the same Copilot Chat features without touching Outlook at all
• New Outlook: if your organization has rolled out new Outlook for Windows, it uses a different codebase from classic Outlook and doesn't share this particular bug

None of these require a new license or extra setup. They're the same Copilot account you already have, accessed through a different door while the classic Outlook door is jammed.

What Should You Do Next?

Try the Show Apps in Outlook checkbox first. It's the fastest fix and Microsoft's own recommended step, and it resolves the issue for most people hitting it. If this doesn't work, move to a new Outlook profile. Keep an eye on Microsoft's known issues page for classic Outlook, since the status will change from "Investigating" to a resolved build number once the permanent fix ships. Once it does, a routine Office update takes care of it without any manual steps.

If you're on a managed work computer, mention the build number (20026.20182 or higher) to your IT department. They might already be tracking this and are able to push the pinned-version fix across your whole team faster than individual workarounds.