Docker Sandboxes v0.30.0 on Windows: Cannot Self-Connect to docker.sock (Daemon Running But Unreachable)

What this error means

ERROR: failed to create sandbox: create runtime: sandboxd error: status 500: failed to create network: Cannot connect to the Docker daemon at unix://...docker.sock. Is the docker daemon running? is a Docker failure pattern reported for developers trying to fix docker sandboxes sbx run failing on windows 11 because sandboxd in-process moby backend cannot connect to its own socket immediately after starting. Based on the imported evidence, treat this as a tool-specific troubleshooting page rather than a generic API error.

Why this happens

GitHub Issue docker/sbx-releases#157 (May 2026): Docker Sandboxes v0.30.0 on Windows 11. sandboxd logs show socket serving correctly, but connecting goroutine 10ms later fails with daemon-not-running error. Secondary issue: stale socket files persist on restart (‘file cannot be accessed by system’). Reproduced with Docker Desktop 29.4.3 + WSL2. Affects Docker Desktop/Sandboxes paid enterprise users.

Common causes

• GitHub Issue docker/sbx-releases#157 (May 2026): Docker Sandboxes v0.30.0 on Windows 11. sandboxd logs show socket serving correctly, but connecting goroutine 10ms later fails with daemon-not-running error. Secondary issue: stale socket files persist on restart (‘file cannot be accessed by system’). Reproduced with Docker Desktop 29.4.3 + WSL2. Affects Docker Desktop/Sandboxes paid enterprise users.

Quick fixes

1. Confirm the exact error signature matches ERROR: failed to create sandbox: create runtime: sandboxd error: status 500: failed to create network: Cannot connect to the Docker daemon at unix://...docker.sock. Is the docker daemon running?.
2. Check the Docker account, local tool state, and provider configuration involved in the failing workflow.
3. Compare the failing environment with a known working setup, then change one configuration value at a time.

Platform/tool-specific checks

• Verify the command, editor, extension, or API client that produced the error.
• Compare local settings with CI, deployment, or editor-level settings when the error appears in only one environment.
• Avoid deleting credentials, local model data, or project settings until the failing scope is clear.

Step-by-step troubleshooting

1. Capture the exact error message and the command, editor action, or request that triggered it.
2. Check whether the failure is account/auth, quota/rate, model/provider, local runtime, or deployment configuration.
3. Review the source evidence below and compare it with your environment.
4. Apply one change at a time and rerun the smallest failing action.
5. Keep the working fix documented for the team or deployment environment.

How to prevent it

• Keep provider/tool configuration documented.
• Record non-secret diagnostics such as tool version, provider name, model name, and command path.
• Add a lightweight check before CI or production workflows depend on the tool.

Sources checked

• https://github.com/docker/sbx-releases/issues/157

Evidence note: GitHub Issue docker/sbx-releases#157 (May 2026): Docker Sandboxes v0.30.0 on Windows 11. sandboxd logs show socket serving correctly, but connecting goroutine 10ms later fails with daemon-not-running error. Secondary issue: stale socket files persist on restart (‘file cannot be accessed by system’). Reproduced with Docker Desktop 29.4.3 + WSL2. Affects Docker Desktop/Sandboxes paid enterprise users.

Related errors

• Docker

FAQ

What should I check first?

Start with the exact ERROR: failed to create sandbox: create runtime: sandboxd error: status 500: failed to create network: Cannot connect to the Docker daemon at unix://...docker.sock. Is the docker daemon running? text and the smallest action that reproduces it.

Can I ignore this error?

No. Treat it as a failed Docker workflow until the root cause is understood.

Is this guaranteed to have one fix?

No. The imported evidence supports the troubleshooting path above, but tool behavior can vary by account, plan, version, provider, and local configuration.

How do I know the fix worked?

Rerun the same command, editor action, or request. The fix is working when that action completes without ERROR: failed to create sandbox: create runtime: sandboxd error: status 500: failed to create network: Cannot connect to the Docker daemon at unix://...docker.sock. Is the docker daemon running?.