New Report button in Outlook 2407 - How do i remove it?

We are still seeing this issue in our tenant, too.

My teammate just talked to MS support about this issue. Response we got was:

Still a known issues on Microsoft's side of things with the report button. They are still working on a fix getting documentation and other published articles on it. Internally they can't share the exact status yet, but it is something they are working on. 

Typical Microsoft answer, I would say.

I did some testing and think I have found the issue here. The "Monitor reported messages in Outlook" setting must be unchecked for the report shield to be removed. I am using KnowBe4 and completely removed the Microsoft report button from our organization's integrated apps. Then I configured the integration between KnowBe4 and Microsoft Defender. In order for this integration to work you need to have the "Monitor reported messages in Outlook" setting checked. I tested multiple machines and once changing this setting and bouncing outlook the report shield will appear if its checked and disappear if not. Microsoft this is causing a big issue for us. One option is to leave the setting checked and allow the integration to work but the report button will still show(You can remove it manually but this is not a solution for large scale operations). Two you can leave the setting unchecked and disable any reporting to Microsoft Defender which is also not a proper solution. Microsoft is there any plans to fix this issue? Currently we can not

have third party report buttons and still report messages to Defender. I hope this helps someone.

I just checked on the fix rollout and it is currently being deployed through the pre-production rings. It has not started going to production yet, but it should be soon. The fix will be in service build 15.20.8115.000. You can check this with the classic Outlook Connection Status Dialog. In the Windows System Tray locate the Outlook icon. Press Ctrl key, right click on the Outlook icon and click Connection Status. The next to last column shows Version. I will get the Known Issue updated with this status shortly, Classic Outlook Report button not removed after setting “Use a non-Microsoft add-in button” - Microsoft Support.

Reference: Description of the Connection Status dialog box - Outlook | Microsoft Learn

Good update. Would love a rough estimate on Shared Mailbox support for the built-in button.

This built in button just started landing in our tenant now (with v2409 on the Monthly Enterprise Channel). So now we have 3 buttons... fun conversations with clients incoming!

Looking forward to getting down to just the built in one, we'll remove the 'Report Message' one when most installs are updated to 2409 and remove our 3rd party home brew one once we've an option for on-prem / shared mailboxes...