BUG: Last logged in user email shown when creating new account in External Tenant

Hello Aleksander Fjellvang [DWARF],

Welcome to the Microsoft Q&A and thank you for posting your questions here.

I understand that you are having BUG: Last logged in user email shown when creating new account in External Tenant.

When a user starts a new account creation, do not reuse any prior session data; instead, force a fresh credential prompt and pre‑set the email that was just verified. Implement below accordingly:

1. Add prompt=login to the authorize URL (or MSAL request) used to render the credentials step. This negates SSO and prevents cached emails from auto‑appearing. For account switching UX, you may prefer prompt=select_account. - https://learn.microsoft.com/en-us/entra/identity-platform/msal-js-prompt-behavior MSAL.js example (SPA):

      const loginRequest = {
        scopes: ["openid"],
        prompt: "login", // or "select_account"
        loginHint: verifiedEmail // see step B
      };
   

   pca.loginRedirect(loginRequest); This uses the documented prompt semantics in Microsoft identity platform/MSAL. - https://learn.microsoft.com/en-us/entra/identity-platform/msal-js-prompt-behavior
2. Then, explicitly tell the IdP which email to use by pass login_hint=<the-just-verified-email> in the same request so the email box is prepopulated with the correct value (and editable if needed). This is the supported way to ensure the email shown is the one you intend, not whatever SSO had cached. - https://learn.microsoft.com/en-us/azure/active-directory-b2c/direct-signin Raw authorize URL pattern (External ID/B2C user flow):

   `https://{tenant}.b2clogin.com/{tenant}.onmicrosoft.com/{userflow}/oauth2/v2.0/authorize`
   

   ?client_id=...&response_type=id_token&scope=openid &redirect_uri=... &prompt=login &login_hint=user@example.com

I hope this is helpful! Do not hesitate to let me know if you have any other questions or clarifications.

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