Microsoft 365: Performing an Internal Admin Takeover on an Unmanaged Tenant

If you’ve created a lot of Microsoft 365 tenants as I have, you’ve likely run into this scenario before. You are attempting to create the tenant using a domain that you own but find that the tenant has already been registered during the Microsoft 365 tenant creation. This is possible because domain ownership is not verified during the tenant creation, as you are actually creating a tenant that initially only has a .onmicrosoft.com domain (ex: yourdomain.onmicrosoft.com). Only after the initial creation are you able to add a TXT record to your DNS registrar in order to confirm domain ownership.

This could have happened because someone else legitimately registered a tenant using your domain, as odd as that may be if they did not actually own the domain. In this case, you may be able to open a Microsoft ticket to find out more information about who registered it and see if you are able to negotiate taking it over. A more likely situation is that a former IT staff member did a self-service sign-up for a cloud service during an initial review of Microsoft 365. It could even be that a current staff member did it but did so long ago that they don’t remember doing so. This is the situation that applies to steps that follow, which outlines performing an admin takeover on an unmanaged tenant.

How to Perform an Internal Admin Takeover on an Unmanaged Tenant

Before proceeding, it is assumed that your tenant was created using self-service sign up, self-service is still enabled in your tenant, and the tenant is unmanaged. Taking over the tenant will not impact any existing information or services.

1. Go to https://powerbi.com/, select Start Free > Start free trial
2. Sign up with an account that uses the domain name of your organization (the one you’re attempting to takeover).
3. Complete the verification process via the email you should receive.
4. Complete the account creation after entering the verification code from your email (this information will be able to be changed on the account once you gain access to the tenant admin center)
5. The become the admin wizard should open. If it doesn’t look for the Admin title and select it.
6. Select Yes, I want to be the admin.
7. You should now be provided instructions to verify your domain ownership by adding a TXT record to your domain registrar.
8. Once you’ve completed adding the TXT record as outlined by the wizard, confirm by selecting Okay, I’ve added the record.

You should have access to the admin center for the tenant using the account you initially created in step 2! Luckily Microsoft has this process available, as I’ve seen several situations arise where a client was unaware they had an existing tenant and would prefer not to have to use an alternative for their .onmicrosoft.com. The main reason for using this domain is that it will be used in conjunction with SharePoint (ex: yourdomain.sharepoint.com). Otherwise, the .onmicrosoft.com domain is not typically public facing.

Now that you have access to your Microsoft 365 tenant don’t hesitate to reach out to the experts at Sikich for assistance with configuring any of the many cloud services available from Microsoft!