Copilot shows blank white page after sign-in (app, Edge and Chrome) – account routed via cosmicRingCookie

The redirect to copilot.com indicates that this personal account has moved—or is completing its move—to the updated Copilot experience; there is no documented user control for removing cosmicRingCookie/userTypeCookie routing, so the blank signed-in experience and missing Pages now require an account-side investigation by Microsoft Support.^1^

Escalate the account migration failure

The results already rule out an ordinary app profile, GPU, browser-extension, local network, and single-browser problem. Do not uninstall or reset the app again.

1. Open the Windows Get Help app.
2. Enter:
   Personal Microsoft account Copilot migration – blank page after redirect to copilot.com and missing Copilot Pages
3. Select Contact Support, choose the Copilot/Microsoft-account-related product offered, and then choose chat or callback. Contact options depend on region, support hours, scenario, and subscription.^2^
4. Ask Support to investigate:
   • the migration state of the personal account to the updated Copilot app;
   • the account-specific signed-in routing failure;
   • whether the account’s Copilot Pages/content migration is pending or failed.
5. Include:
   • when the failure began;
   • that signed-out Copilot loads but signing in produces a blank page;
   • that it reproduces in the Windows app, Edge, and Chrome;
   • the final URL parameters redirfrom=userTypeCookie and redirfrom=cosmicRingCookie;
   • the hasChildNodes JavaScript exception and CORS failure;
   • confirmation that fresh profiles, reinstall, GPU disabling, extensions, security software, and network checks did not change it;
   • a screenshot and, if Support requests it, a browser HAR/console export captured during sign-in.

Do not post the HAR publicly: it can contain authentication URLs, cookies, account identifiers, and tokens.

If the Copilot interface becomes usable enough to access its menu, also submit … → Send feedback → Report a problem with the same details. That is Microsoft’s documented reporting route for updated-app migration problems.^1^

Recovering the existing Pages

Microsoft states that personal-account users are moved to the updated app and that their chats and content move with them; users of both previous experiences have their content merged into the single updated app.^3^

For missing content:

• Sign in using exactly the same personal Microsoft account and authentication method previously used.
• Once copilot.com loads, check for an in-app link to existing content.
• Allow time for migration and synchronization; Microsoft notes that content can remain unavailable while it is moving.^1^
• If any Pages become accessible in another client or session, copy or export their contents immediately. When Pages remain blank everywhere, there is no confirmed user-side restoration procedure; account/backend investigation is required.^4^

The working m365.cloud.microsoft/chat session is not evidence that the personal Pages are available there. Copilot keeps personal and work/school experiences separate, and data does not flow between those account types.^5^

One remaining conditional browser check

Only if third-party cookies have not already been explicitly allowed, test once with them enabled—not merely in InPrivate mode, where they can be blocked by default:

• Edge: Settings → Cookies and site permissions → Manage and delete cookies and site data → turn Block third-party cookies off.
• Chrome: Settings → Privacy and security → select Allow third-party cookies.

Copilot web authentication and license validation can depend on third-party cookies.^6^ If this was already enabled, or the same blank page remains, return it to the preferred privacy setting and proceed with Support; the cross-client, account-specific migration failure is the actionable path.

References

1. Troubleshoot Your Content in the Updated Copilot App | Microsoft Support
2. Get Help for Microsoft personal account users | Microsoft Support
3. Copilot App Updates for Personal, Work, and School Accounts | Microsoft Support
4. Copilot Pages - Microsoft Q&A
5. Get started with the Microsoft Copilot app
6. I am getting license validation errors with Copilot | Microsoft Support