[BUG] Cowork stuck on 'Authenticating' — OAuth exchange hangs with no response (macOS, M3)

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?
Cowork mode is permanently stuck on the authenticating screen after sending any prompt. Chat and Claude Code work fine. The issue started after updating to the latest Claude Desktop release (April 2, 2026).

Environment
Platform: macOS, Apple Silicon (M3)
App version: Claude Desktop (latest, updated April 2, 2026)
macOS version: [add yours]
Plan: [add yours e.g. Pro/Max]

Symptoms
Write a prompt in Cowork → UI shows "Authenticating" → hangs indefinitely
Regular Chat: works fine
Claude Code: works fine
Clean install performed, VM allowed to fully initialise — issue persists
Clearing vm_bundles and local-agent-mode-sessions did not resolve

Logs
From ~/Library/Logs/Claude/claude.ai-web.log:
2026-04-07 12:14:39 [info] LocalAgentModeSessions.start:
2026-04-07 12:14:39 [info] using oauth config {
apiHost: 'https://api.anthropic.com',
clientId: 'a473d7bb-17ac-43a7-abc0-a1343d7c2805',
redirectUri: 'https://console.anthropic.com/oauth/code/callback',
scope: 'user:inference user:file_upload user:profile',
domain: '.claude.ai'
}
2026-04-07 12:14:39 [info] [oauth] looking up token for orgId=<orgid>, cacheKey=a473d7bb-17ac-43a7-abc0-a1343d7c2805:<orgid>:https://api.anthropic.com:user:inference user:file_upload user:profile
2026-04-07 12:14:39 [info] [oauth] no cached token found for orgId=<orgid>
2026-04-07 12:14:39 [info] [oauth] performing fresh oauth exchange for orgId=<orgid>
2026-04-07 12:14:39 [info] [VM] getVMStorageSubpath: vmStorageDir=/Users/<user>/Library/Application Support/Claude/claude-code-vm, subpath=Users/<user>/Library/Application Support/Claude/claude-code-vm
2026-04-07 12:14:39 [warn] Transcript not found for session local_24004ac9-14b4-45de-8298-c765ae3502b0 (cliSessionId: none)

Key observation: The log ends immediately after performing fresh oauth exchange — no success, no error, no timeout. The exchange silently hangs. There are no subsequent [oauth] log entries at all.
Also present in logs (likely a side-effect, not root cause):
[warn] MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 AutoUpdater listeners added.

Root cause hypothesis
Cowork uses a distinct OAuth client ID (a473d7bb-17ac-43a7-abc0-a1343d7c2805) separate from Chat/Code (9d1c250a-e61b-44d9-88ed-5944d1962f5e). The fresh token exchange against Anthropic's OAuth endpoint for this client ID appears to produce no response — no token, no error — causing an indefinite hang. This is consistent with issue #33216.

What I've tried
Clean uninstall and reinstall of Claude Desktop
Waited for full VM initialisation before sending prompt
Cleared ~/Library/Application Support/Claude/vm_bundles
Cleared ~/Library/Application Support/Claude/local-agent-mode-sessions
Cleared Local Storage and Session Storage
Checked Keychain Access for stale Claude/Anthropic entries
Sign out and back in

What Should Happen?

Cowork authenticates successfully and begins executing the task.

Actual behaviour
UI shows "Authenticating" indefinitely. No error is surfaced to the user.

Error Messages/Logs

2026-04-07 12:19:11 [info] [RemotePluginManager] Sync complete: 0 downloaded, 0 removed, 0 orphans cleaned
2026-04-07 12:19:11 [info] [oauth] obtained new token for orgId=<orgid>, caching
2026-04-07 12:19:11 [warn] Blocked permission check {
  permission: 'background-sync',
  requestingOrigin: 'https://a.claude.ai/',
  requestingUrl: 'https://a.claude.ai/isolated-segment.html?v=dev',
  isMainFrame: false,
  topFrameUrl: 'https://claude.ai/task/new'
}
2026-04-07 12:19:17 [info] [VM] getVMStorageSubpath: vmStorageDir=/Users/<uesr>/Library/Application Support/Claude/claude-code-vm, subpath=Users/<uesr>//Library/Application Support/Claude/claude-code-vm
2026-04-07 12:19:38 [info] [EventLogging] Flushing 13 events
2026-04-07 12:20:33 [info] LocalAgentModeSessions.start:
2026-04-07 12:20:33 [info] using oauth config {
  apiHost: 'https://api.anthropic.com',
  clientId: 'a473d7bb-17ac-43a7-abc0-a1343d7c2805',
  redirectUri: 'https://console.anthropic.com/oauth/code/callback',
  scope: 'user:inference user:file_upload user:profile',
  domain: '.claude.ai'
}
2026-04-07 12:20:33 [info] [oauth] looking up token for orgId=<orgid>, cacheKey=a473d7bb-17ac-43a7-abc0-a1343d7c2805:<orgid>:https://api.anthropic.com:user:inference user:file_upload user:profile
2026-04-07 12:20:33 [info] [oauth] no cached token found for orgId=<orgid>
2026-04-07 12:20:33 [info] [oauth] performing fresh oauth exchange for orgId=<orgid>
2026-04-07 12:20:34 [info] [VM] getVMStorageSubpath: vmStorageDir=/Users/<user>/Library/Application Support/Claude/claude-code-vm, subpath=Users/<user>/Library/Application Support/Claude/claude-code-vm
2026-04-07 12:20:34 [warn] Transcript not found for session local_6e6dd954-8766-47db-9a81-28b745d41d73 (cliSessionId: none)

Steps to Reproduce

1. Open Claude Desktop on Mac
2. Select Cowork tab
3. Enter prompt

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.77 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_