[BUG] Claude Desktop app on macOS cannot authenticate due to Google primary email conflict

Preflight Checklist

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

What's Wrong?

What's Wrong?
The Claude Desktop app on macOS will not authenticate into my existing account. It keeps creating a new account instead of recognizing my original one.
Root Cause:
Google recently released a feature allowing users to create a new primary email address on an existing Google account. My original Claude account was created with [vegashomegoals@gmail.com](mailto:vegashomegoals@gmail.com). I updated my Google primary email to [jill.goldberg.mi@gmail.com](mailto:jill.goldberg.mi@gmail.com). These are the same underlying Google account — vegashomegoals is now an alias. When the desktop app attempts authentication, Google automatically authenticates as [jill.goldberg.mi@gmail.com](mailto:jill.goldberg.mi@gmail.com), which the desktop app treats as a new user instead of my existing account.
What I Tried:

Email login with [vegashomegoals@gmail.com](mailto:vegashomegoals@gmail.com)
Google authentication
Incognito window
Unlinking Claude from Google connections at myaccount.google.com/connections
Unlocking Mac Keychain via Terminal (security unlock-keychain ~/Library/Keychains/login.keychain-db)

What Works:
Web app at claude.ai works perfectly with full account history and Pro subscription intact.
Operating System: macOS
Support Conversation ID: 215473943992646

What Should Happen?

The Claude Desktop app should recognize that [vegashomegoals@gmail.com](mailto:vegashomegoals@gmail.com) and [jill.goldberg.mi@gmail.com](mailto:jill.goldberg.mi@gmail.com) are the same underlying Google account and authenticate into the existing account rather than creating a new one. Additionally, Anthropic should update the desktop app to handle Google's new primary email feature gracefully, as this will affect any user who has adopted this new Google feature.

Error Messages/Logs

Steps to Reproduce

1. Create a Claude account using a Gmail address ([vegashomegoals@gmail.com](mailto:vegashomegoals@gmail.com))
2. Use Google's new primary email feature to change the primary address on that Google account to a new address ([jill.goldberg.mi@gmail.com](mailto:jill.goldberg.mi@gmail.com)) — the original address becomes an alias on the same account
3. Download and open the Claude Desktop app on macOS
4. Attempt to log in using either Google authentication or email login with the original email address
5. Google automatically authenticates using the new primary email address instead
6. Claude Desktop creates a new account instead of recognizing the existing account tied to the original email

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

N/A - Claude Desktop App

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

This bug affects the Claude Desktop app, not Claude Code. It is caused by Google's recently released feature that allows users to change their primary Gmail address while keeping the original as an alias on the same account. The desktop app does not handle this scenario and has no workaround available to the end user. Support conversation ID: 215473943992646