[BUG] Cowork: "Failed to create bridge sockets after 5 attempts" after auto-update to Claude.app 1.3036.0

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?

Cowork (Claude.app desktop) fails on every spawn with "Failed to create bridge sockets after 5 attempts" immediately after auto-update to Claude.app 1.3036.0. Every Claude Code process inside the Cowork VM exits code=1 within ~2 seconds of spawn. Happens across all projects and all new chats. Claude.ai web (non-Cowork) is unaffected.

What Should Happen?

Claude Code should spawn successfully inside the Cowork VM, create its bridge sockets, and accept input like it did before the 1.3036.0 update.

Error Messages/Logs

# From ~/Library/Logs/Claude/cowork_vm_node.log

2026-04-16 12:08:18 [info] [Spawn:vm] id=00728e55 Spawn succeeded in 130ms
2026-04-16 12:08:20 [warn] [vm-stderr 00728e55] Error: Failed to create bridge sockets after 5 attempts
2026-04-16 12:08:20 [info] [Process:00728e55] Exited, code=1, signal=null, duration=1958ms, oom=false

Same pattern on every spawn — 11+ occurrences since the auto-update.
Claude Code SDK in VM: 2.1.111
VM bundle: 5680b11bcdab215cccf07e0c0bd1bd9213b0c25d

Steps to Reproduce

1. Open Claude.app 1.3036.0 on macOS.
2. Open any Cowork chat (existing or new project).
3. Send any message.
4. Observe "Claude Code process exited with code 1" immediately.
5. Check ~/Library/Logs/Claude/cowork_vm_node.log — every spawn shows "Failed to create bridge sockets after 5 attempts".

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

1.3035.x (exact unknown — last working session was ~2 hours before auto-update today 2026-04-16)

Claude Code Version

2.1.111 (bundled SDK inside Cowork VM)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

This is not a Claude Code CLI terminal bug — it's the Cowork VM inside Claude.app desktop. The form doesn't have a perfect category for it.

Context that narrows it to the 1.3036.0 build:

• App bundle at /Applications/Claude.app mtime: 2026-04-16 (today, auto-updated).
• /Applications parent mtime: 11:21 — exact moment of the quit that triggered the auto-update.
• First "Failed to create bridge sockets" error in the log: 11:24, 3 minutes after the update.
• Fresh DMG downloaded from claude.com/download reports the same 1.3036.0 — no downgrade path available.

Things already tried (none fixed it):

• Full app quit + relaunch.
• Wiped SDK 2.1.111 and .sdk-version marker — SDK reinstalls, bug persists.
• Deleted entire VM bundle (/vm_bundles/claudevm.bundle) and claude-code-vm dir — VM rebuilds from scratch (~3.5 min download), bug persists.
• Reinstall from fresh DMG — same version, no change.
• Tested across multiple projects / new chats — same failure.

The spawn itself always succeeds ("Spawn succeeded in ~100ms"); the failure is inside the claude binary when it attempts to create its bridge sockets. Strongly points to a regression in the 1.3036.0 build rather than local state corruption.