Remove custom domain from o365 tenant

Question

Remove custom domain from o365 tenant

HASSAN BIN NASIR DAR 391

Hi,

I am doing o365 tenant to tenant migration including everything.

Now I want to remove my custom domain from the source tenant. Can you please guide me what should I preparing before migration? thanks

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Answer 1

CaseyYang-MSFT 10,461

Hi @HASSAN BIN NASIR DAR ,

1.Change user UPNs to onmicrosoft.com. Always do that step first, before starting removal of email addresses. The step can be easlily automated.
2.Remove email addresses containing vanity domain from user mailboxes, mail users, groups. Again there are scripts on the internet that allow you automated removal.
3.Then in the admin center, go to the Settings > Domains page, select the domain that you want to remove.

For More Details: Office 365 Tenant to Tenant Migration: Domain removal techniques
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HASSAN BIN NASIR DAR 391 Reputation points

2021-11-05T10:07:18.72+00:00

Hi,

> 1.Change user UPNs to onmicrosoft.com. Always do that step first, before starting removal of email addresses. The step can be easlily automated.

My all accounts already have Alias with onmicrosoft.com. Because when I migrated all users that time I used source and destination onmicrosoft.com Alias. Are you talking about this?

> 2.Remove email addresses containing vanity domain from user mailboxes, mail users, groups. Again there are scripts on the internet that allow you automated removal.

Can we do it on portal? Can you help to send that script?

> 3.Then in the admin center, go to the Settings > Domains page, select the domain that you want to remove.

When I will remove my custom domain. After removal my accounts will stay there with onmicrosoft.com?

Regards,
CaseyYang-MSFT 10,461 Reputation points

2021-11-08T10:11:20.793+00:00

Hi @HASSAN BIN NASIR DAR ,

Here is some arctiels for reference:

SharePoint Online: Remove User from Site Collection using PowerShell
Remove Domain from Office 365 Best Method How to Guide

Note: Microsoft is providing this information as a convenience to you. The sites are not controlled by Microsoft. Microsoft cannot make any representations regarding the quality, safety, or suitability of any software or information found there. Please make sure that you completely understand the risk before retrieving any suggestions from the above link.
HASSAN BIN NASIR DAR 391 Reputation points

2021-11-08T18:23:42.123+00:00

Hi,

I have 150 users mailboxes. 30 shared and resource mailboxes, one drive and teams.

According to the above article, I should take a backup for all services before removing the custom domain.

Can you tell me the powershell script or GUI for the backup?

/Hassan
CaseyYang-MSFT 10,461 Reputation points

2021-11-10T10:04:37.35+00:00

Hi @HASSAN BIN NASIR DAR ,

Per my research, i didn't figure out how to remove multiple mailboxes with powershell. I suggest you create a service request with Microsoft for furthur help about how to remove custom domain.

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Remove custom domain from o365 tenant

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