How to remove [External] from Outlook emails, users are getting furious

Dear Jim Bolinski (jim),

Good day! Thank you for posting to Microsoft Community. We are happy to help you!

In general, the internal/external subject of a message is defined by the source of the email, so I'd like to gather the following information from you to narrow down the issue:

Are you sure that the messages you receive with external subjects are from internal users?

All the messages you receive come with an external subject?

If you are using the Outlook Desktop Client, try logging in to the OWA (Outlook web app) with your account and ask another user to send a test email, then check OWA to see if you get the same error as on the Outlook Desktop Client.

Are all users inside your organization experiencing this issue?

If you find some error messages or error codes, please share the screenshot with me so that I can do more research, thank you.

Thanks in advance for your understanding! Your patience and cooperation will be highly appreciated. Hope you all the best!

Sincerely,

Kerry Chen | Microsoft Community Moderator

Kerry,

This is across all tenants, all users, whenever they receive an email since the most recent M365 updates get a tag in their Subject line [External] which is true, however unwanted by many users. I need to know where to turn off this "feature"

Dear Jim Bolinski (jim),

Thanks a lot for your patience and understanding!

If this tag is just not needed, then we cannot implement it so far because it is the result of a product update. It is determined by the relevant design and development department of the product. So I think your suggestion is very meaningful, I also believe that this is the voice of many users, everyone is anxiously looking forward to early improvement, in order not to waste more time for you, better to help you, I strongly recommend that you upload your valuable suggestions to outlook feedback, let the relevant technical developers and designers see your valuable suggestions, please believe that Microsoft relevant departments will try to improve themselves after seeing your valuable suggestions, your valuable opinions will also help more users, make the work more efficient.

For advice on how to give back to you, please kindly refer to: click File>choose feedbback>select suggest a feature>input your suggestions

At the same time, you can also use this link to see if the feature you want to implement is already under development by Microsoft, and please kindly always click on it to get the development progress: Microsoft 365 roadmap

Wish you have a wonderful day and always stay safe!

Sincerely,

Kerry Chen | Microsoft Community Moderator

Thank you for your response, although it is very discouraging that it must filter through the Relevant Team, whom I am sure feel they are so much above us lowly users and know what is best for us.

I think whenever there is a "feature" added, there should be a method to disable it, or to allow an Opt-In option if someone thinks it might be useful. I have 63 open tickets from very upset users thinking it was something I did.

We have found a solution to remove the annoying [External] tag in the subject line

Run at the tenant level the command:

Set-ExternalInOutlook -Enabled $false

It takes about 24 hours to take effect, and only remove the annoying tag from the new emails, but at least we have 154 users off our back now.

That was about the most ridiculous "feature" ever added. It breaks the ability to track conversations, and is just annoying to the users. 95% of all emails is external anyway, why would tagging it make any difference.

Hope this helps some other sysadmins that have users upset at them