[BUG] OAuth and magic-link login redirect existing Max subscriber to "Let's create your account" onboarding — browser and desktop locked out, iOS + Console still authenticated

Preflight Checklist

• I have searched existing issues and this hasn't been reported yet
• This is a single bug report (please file separate reports for different bugs)
• I am using the latest version of Claude Code

What's Wrong?

Logging in on claude.ai and the Claude Desktop app resolves to the "Let's create your account" onboarding page instead of my existing Max account. Email verification completes successfully, but the backend does not map the verified identity to my account. No error is surfaced — it silently falls through to new-user onboarding.

Broken: claude.ai in Chrome, Safari and Firefox including private windows, on two separate machines, with two different Google accounts, plus Claude Desktop for macOS.

Still working on the same account: Claude iOS app (authenticated, active Max plan visible), console.anthropic.com, and scheduled cloud tasks that keep running and making outbound connector calls. So the account exists and the subscription is active — only the browser and desktop auth handoff is broken.

Additional diagnostic: a session still logged in on my office iMac was dropped to the onboarding screen the moment I opened the window. Existing sessions are being actively rejected, not merely failing to authenticate.

I have deliberately NOT clicked "Create account", to avoid creating a duplicate as documented in the related issues.

Locked out since 13 September. Support ticket #133406865 open since 16 September, where an agent confirmed the account is active with no usage violations. Two templated replies since, both about clearing the desktop app's cache. No engineering escalation confirmed.

What Should Happen?

Logging in with my existing email, via Google OAuth or email magic link, should resolve to my existing account with my conversations and Max subscription — not to the account-creation flow.

The web auth callback should never silently fall through to new-user onboarding for an email with an active subscription. It should surface an explicit error and route to support, rather than offering to create a duplicate account under the same email.

Error Messages/Logs

Steps to Reproduce

1.    Go to claude.ai in any browser, or open Claude Desktop on macOS
    2.    Click "Continue with Google" and authenticate with the account email
    3.    Google authentication completes successfully
    4.    Observe: redirected to claude.ai/onboarding showing "Let's create your account", with the email shown as verified at the bottom
    5.    Repeat with "Continue with email" and the magic link — identical result
    6.    Repeat in a clean private window with no cookies or extensions — identical result
    7.    Repeat on a second machine that has never run the desktop app — identical result

Also tried without success: clearing cache and cookies, three different browsers, two different Google accounts. No VPN, proxy or DNS filtering in use.

Claude Model

Not sure / Multiple models

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

N/A

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

On 14 September, conversation ID 215475937472916, I was given roughly twenty minutes of login troubleshooting with no mention of any account problem. Only after I asked about refund eligibility was I told my subscription had been cancelled for a Terms of Service violation, and directed to the appeals process. The same agent stated four times that no organization was linked to my address, while my own account settings display one.

The appeal form at claude.ai/restricted requires being logged in — the exact thing that fails. Three emails to the safeguards address each produced an automated reply within a minute pointing back to that form, and the ticket was closed each time.

On 16 September, in ticket #133406865, a support agent confirmed in writing that my account is active and that no usage violations were detected, contradicting what I was told on 14 September. Since then: two templated replies about clearing the desktop app's cache and reinstalling, neither addressing that the browser fails identically on a machine that has never run the desktop app.

Impact: paying Max subscriber, locked out of web and desktop since 13 September, running a business on this account from a phone. Every remedy I'm pointed to — data export, subscription management, the ban appeal form — sits behind the same broken login, so I cannot export my data, cancel my subscription, or file an appeal without the access I am trying to restore.

Account details and conversation IDs available privately on request.

No repository files, tests, or entry points are identified. Start by determining whether the reported web and Claude Desktop authentication flow is implemented in this repository, then reproduce the Google OAuth and email magic-link paths. Done means an existing subscribed account reaches its account rather than onboarding, with an explicit support-facing error when mapping fails.