Corporate account merged with personal MSA and stuck as guest (#EXT#) in wrong tenant

Question

My corporate account has been incorrectly merged with my personal Microsoft account

(Hotmail/MSA). As a result, my corporate user now appears as a guest (#EXT#) inside the

tenant mlancellottihotmail.onmicrosoft.com, which is not my organization's tenant.

Because of this identity issue:

. I cannot access or create a proper organizational tenant.

. I cannot switch directories because only the Hotmail-generated tenant is available.

. I cannot delete the guest (#EXT#) identity because the system treats it as my own

principal.

. I cannot register Partner Center or any Microsoft business services.

. I cannot open support tickets from the affected tenant because it has no valid

support plan.

I need Microsoft to perform a backend cleanup of my identity:

1. Remove the guest (#EXT#) identity associated with my Hotmail account.
2. Fully detach my MSA (Hotmail) from my corporate identity.
3. Restore my corporate account as a native user in a valid organizational tenant.
4. Release my corporate domain so I can create or access the correct tenant.

This issue prevents me from using any Microsoft business services and from managing

my organization's identity.

Additional Details

. Current visible tenant: mlancellottihotmail.onmicrosoft.com

. Corporate account is incorrectly treated as a guest (#EXT#).

· No other tenants appear in the directory switcher.

. Cannot create a new tenant because the identity is locked to the MSA tenant.

. Need backend intervention to repair the identity and separate the accounts.

Answer 1

Dear @Mariano Lancellotti,

Thank you for reaching out to the Microsoft Q&A forum.

Based on the information you provided, I understand that you are currently experiencing an issue with your account and are unable to sign in.

Regarding the #EXT# appearing in your account name, this indicates that your account is marked as a guest account in another tenant. For example, if your original account is ******@domain1.com and you are added as a guest to the tenant domain2.com, when accessing resources in that tenant (such as OneDrive or SharePoint), your account may appear as a_domain1_com#EXT#@domain2.com. This is expected behavior for guest accounts.

To regain access, please try signing out of the account and then signing in again.

If the issue persists, please clear your browser cache using the steps below and try again:

Google Chrome

Menu (⋮) → Settings → Privacy and security → Clear browsing data →

Select Cached images and files, choose All time, then click Clear data

Microsoft Edge

Menu (⋮) → Settings → Privacy, search, and services → Clear browsing data →

Select Cached images and files, choose All time, then click Clear data

You can also create a new user profile of browser to have a new clean, fresh browser.

If you have any updates or if the issue continues, please feel free to let me know. I look forward to your response.

Answer 2

The described situation matches an account overlap/mix‑up between a personal Microsoft account (MSA/Hotmail) and a work account, which cannot be fixed by self‑service alone. The only supported remediation steps from documentation are:

1. Rename the personal Microsoft account so it no longer uses the corporate email/domain.
2. Work with the correct organizational tenant’s admin/support to re-establish the work identity and access.
3. Use official Microsoft support channels when tenant/identity lockout prevents self‑service.

Based on the available guidance, the following actions are supported:

1. Rename the personal MSA (Hotmail) to remove conflict with the corporate identity
   When a personal MSA uses the same email/name as a work account, it can cause exactly the type of identity confusion described (work account treated as guest, wrong tenant, etc.). Microsoft no longer supports this overlapping pattern. The documented workaround is to rename the personal Microsoft account so it no longer conflicts with the work identity.
   • Follow the steps in this article to rename the personal Microsoft account to a different email address that does not use the corporate domain.
   • This is also recommended in Partner/DevOps scenarios to avoid being prompted to choose between accounts and to prevent sign‑in issues.
   Renaming the MSA does not itself delete the guest object or move the corporate account, but it removes the primary cause of the overlap and is a prerequisite for any clean separation.
2. Confirm and use the correct work vs personal account at sign‑in
   After the MSA is renamed, sign in explicitly with the work account (corporate email) wherever possible, and select the work account when prompted between “Work or school” and “Personal” accounts. This is required to:
   • Access Partner Center and other Microsoft business services with the correct identity.
   • Ensure the correct tenant is targeted when signing in.
   Documentation notes that work and personal accounts can look identical (for example, ******@contoso.com), and that choosing the wrong one leads to missing capabilities in Partner Center and related services.
3. Have the correct tenant’s admin adjust or recreate the corporate identity
   The actions requested such as:
   • Removing or cleaning up the guest #EXT# object in a tenant,
   • Restoring the corporate account as a native user in the correct organizational tenant,
   • Releasing the corporate domain from an incorrect tenant,
   all require tenant‑level administrative control and, in some cases, Microsoft support intervention. These operations cannot be performed from the guest account itself. The supported path is:
   • Identify the correct organizational tenant that should own the corporate domain and identity.
   • Have a Global Administrator in that tenant manage the user object and domain configuration (for example, removing incorrect domain associations, re‑creating the user as a native account, or adjusting UPNs and aliases).
   • If the domain is tied to a wrong tenant and no admin access exists, a support ticket with Microsoft is required so that the Data Protection/identity team can validate ownership and perform backend changes.
4. Use Microsoft support for tenant/identity lockout scenarios
   When there is no way to access the correct tenant or there is a lockout (for example, only a guest account exists, or no Global Admin is available), the documented resolution path is through Microsoft support, not self‑service tools. In similar lockout/MFA cases, Microsoft’s Data Protection team is engaged via a support ticket to restore access or adjust tenant configuration. In this scenario, because:
   • The only visible tenant is the Hotmail‑based tenant,
   • The corporate identity is stuck as a guest,
   • No valid support plan is available in that tenant,
   the next step is to open a support request through an available channel that does not depend on that tenant’s support plan (for example, via another Microsoft subscription, Partner, or Nonprofit contact channel, or general Microsoft support entry points). The support team can then:
   • Validate domain and identity ownership,
   • Remove or correct the guest object in the incorrect tenant,
   • Help release or reassign the domain to the correct tenant,
   • Assist in re‑establishing the corporate account as a native user.
5. Prevent future lockouts once the tenant is corrected
   After the correct tenant and identity are restored, it is recommended to:
   • Keep the personal MSA and work account clearly separated (different sign‑in addresses).
   • Create an emergency access (break‑glass) account in Microsoft Entra ID to avoid being locked out of the organization in future sign‑in or MFA issues.

These steps align with Microsoft’s documented guidance for overlapping MSA/work accounts and tenant lockout scenarios. The core actions that can be taken directly are renaming the personal MSA and ensuring the correct account is used at sign‑in; all deeper identity/tenant cleanup and domain release requires Microsoft support and/or a Global Admin in the correct tenant.

---

References:

• How to Troubleshoot Common Issues
• Troubleshoot sign-in issues and account access problems
• Change your organization connection to a different Microsoft Entra ID
• Tenant modification
• I need to reset my mfa methods - Microsoft Q&A
• Severity A Situation - Locked out of global admin account (MFA) - business down - Microsoft Q&A