Microsoft 365 Business tenant – lost sole Global Administrator username – tenant recovery required

Please note that this forum is a community support space, so I don’t have the ability to access tenant data or perform actions such as resetting MFA/security information directly. I can only guide you based on documented processes and experience, but I will do my best to point you in the right direction so this can be resolved properly.

Dear @Virgile Amaudric du Chaffaut,

I hope you’re having a good day. 

Thank you for providing such detailed information about your situation.

I understand that you are the owner of the Microsoft 365 Business tenant and that the primary challenge is that you no longer know the username of the sole Global Administrator account.

Since you have indicated that there are no other Global Administrators in the tenant, recovery will need to be handled by Microsoft Support through their account and tenant ownership verification process. The information you mentioned having available, such as the Tenant ID, purchase records, renewal confirmations, billing information, and proof of ownership, can be very helpful during that verification process.

I understand that you have already attempted to contact Microsoft Support without success. However, I would still recommend trying again during business support hours and, if possible, at a different time of day. Based on my experience with similar administrator lockout scenarios, it can sometimes take multiple attempts before reaching the appropriate support queue or a support representative who can correctly route the request.

Please try to find the related hotline number to call the frontline let them raise a ticket for you: Customer service phone numbers - Microsoft Support 

When speaking with the automated system, you may find it helpful to indicate:

Automated system: Are you calling as a private individual or a business customer?

You: Business customer.

Automated system: What do you need help with today?

You: Authentication problem.

Automated system: Which Microsoft product or service is affected?

You: Microsoft 365 for business.

Automated system: Can't sign in to the Microsoft 365 Admin Center?

You: Yes.

Automated system: Do you have another administrator in your organization?

You: No, I'm the only administrator.

Automated system: Are you a global administrator for the affected tenant?

You: Yes.

Automated system: Are you calling about an existing support case, or would you like to create a new one? You: I need to create a new support case.

In many cases, the automated system will then indicate that it can connect you with a support representative who can help create a support request and forward the case to the appropriate recovery team.

If the subscription was originally purchased through a Microsoft partner or reseller, you may wish to contact that organization as well, as they may be able to assist with opening a support request or guiding you to the appropriate support channel.

Alternatively, you can try set up a new trial tenant and submit your support request, please follow this link to create a trial tenant: Compare Office 365 Enterprise Pricing and Plans | Microsoft 365 - after that you will be able to access to Microsoft 365 Admin Center to raise the ticket

Assuming that you have already created an account after registering a free trial and you can go to Microsoft 365 admin center and click Support > Help & support icon to raise your ticket. The agent will be able to create a ticket for you under the affected tenant and then transfer this ticket to Data Protection team who could help you to regain access.

Please mention that you are raising ticket on behalf of the affected tenant that you do not have access to. The support team will help you to create ticket on the affected tenant then later on the Microsoft Data Protection team will assist you.

Note: This process will take more time than usual (7-14 working days) for your account to get access again as Data Protection is always overwhelmed with the number of tickets. I do not have access to Microsoft internal system to assist or push this process to be quicker.

If you do create the trial and it resolves the issue, please remember to cancel the subscription afterward to avoid any related charges. This new trial tenant will not give you access to any of the data or settings in your original locked tenant. It is solely a temporary means to contact Microsoft support.   

I hope my information is helpful. Please give me any updates once you get this resolved.

Warm regards,  

If the answer is helpful, please select "Yes, accept answer". If you have any questions or new updates, please feel free to comment below.