[BUG] Cowork: Claude Code process exits with code 1 on every query — "Failed to create bridge sockets after 5 attempts" on Windows 11 25H2

Title

[BUG] Cowork: Claude Code process exits with code 1 on every query — "Failed to create bridge sockets after 5 attempts" on Windows 11 25H2

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

In Cowork on Windows 11 (25H2), every query fails with Claude Code process exited with code 1. The failure is immediate (~1–2 seconds after send) and 100% reproducible across sessions and across models (seen on both claude-opus-4-6 and claude-opus-4-7).

The VM itself starts up fine — Network status: CONNECTED, API reachability: REACHABLE, SDK installs successfully (v2.1.111), process spawn succeeds. The process then dies on stderr with:

[vm-stderr] Error: Failed to create bridge sockets after 5 attempts
[Process] Exited, code=1, signal=null, duration=~1500ms, oom=false

This pattern repeats identically on every query. The Claude Code CLI works correctly on the same machine with the same auth, so the issue is isolated to the Cowork host↔guest socket bridge on Windows.

Expected Behaviour

The spawned Claude Code process should establish its bridge sockets with the host and handle queries normally.

Steps to Reproduce

1. Install Claude Desktop 1.3036.0 (cf521c) on Windows 11 Pro 25H2
2. Open Cowork and start a new session in any project
3. Send any query
4. Observe immediate Claude Code process exited with code 1 error in the UI
5. %APPDATA%\Claude\logs\cowork_vm_node.log shows Failed to create bridge sockets after 5 attempts for every spawned process

Environment

• Claude Desktop version: 1.3036.0 (cf521c)
• Bundled Claude Code SDK: 2.1.111
• OS: Windows 11 Pro, 25H2
• Models tried: claude-opus-4-6, claude-opus-4-7 (both fail identically)
• CLI working: yes, /usr/local/bin/claude works fine outside Cowork with the same OAuth token
• Started: after recent Cowork auto-update

Log Output

%APPDATA%\Claude\logs\cowork_vm_node.log — representative failure (full log available on request):

2026-04-16 20:19:11 [info] [VM:start] Still waiting for guest connection... 10264ms elapsed, 21 polls
2026-04-16 20:19:12 [info] [VM] Network status: CONNECTED
2026-04-16 20:19:12 [info] [VM:steps] sdk_install started
2026-04-16 20:19:12 [info] [postConnect] Installing SDK: version=2.1.111
2026-04-16 20:19:14 [info] [VM] API reachability: REACHABLE
2026-04-16 20:19:15 [info] [VM:steps] sdk_install completed (2983ms)
2026-04-16 20:19:15 [info] [VM:start] Startup complete, total time: 15858ms
2026-04-16 20:19:18 [info] [Spawn:create] id=40bb2790-... cmd=/usr/local/bin/claude args=... --model claude-opus-4-6 ...
2026-04-16 20:19:18 [info] [Spawn:vm] id=40bb2790 OAuth token approved with MITM proxy
2026-04-16 20:19:19 [info] [Spawn:vm] id=40bb2790 Spawn succeeded in 295ms
2026-04-16 20:19:20 [warn] [vm-stderr 40bb2790] Error: Failed to create bridge sockets after 5 attempts
2026-04-16 20:19:20 [info] [Process:40bb2790] Exited, code=1, signal=null, duration=2180ms, oom=false

Three consecutive sessions (IDs 40bb2790, 9131eb14, bf3c843f) all failed with the same Failed to create bridge sockets after 5 attempts error.

Troubleshooting Already Attempted

• Restarted Cowork and rebooted the machine — no change
• Confirmed VM is otherwise healthy (network connected, API reachable, SDK installs)
• Confirmed CLI (claude) works on the same machine with the same auth — bug is Cowork-specific
• Tried both claude-opus-4-6 and claude-opus-4-7 — both fail identically

Additional Notes

Given the error is specifically about creating bridge sockets (host↔VM guest loopback), plausible causes on the host side include antivirus/endpoint protection intercepting loopback traffic, a VPN client, or a Windows 11 25H2 networking regression. Happy to test specific hypotheses or provide additional logs.