cloudflare / cloudflare/workerd

wrangler dev consistently crashes with "access violation" (0xc0000005) on Windows 11

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bug windows
Dominant language
C++
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Description

### What versions & operating system are you using?

⛅️ wrangler 4.23.0, node v22.15.0, npm v11.4.2, bun v1.2.18

### Please provide a link to a minimal reproduction

_No response_

### Describe the Bug

**Summary of the Problem:**
The `workerd` runtime used by `wrangler dev` seems to have a critical incompatibility with my Windows environment, leading to a `0xc0000005` exception.

**Troubleshooting Steps I've Exhaustively Performed:**

1. **Verified System Dependencies:** Confirmed the latest Microsoft Visual C++ Redistributables (x64 & x86) are installed.
2. **Isolated the Project:** The crash occurs even with a brand new, minimal project created by `npx wrangler init`. This rules out my specific project's code or configuration.
3. **Isolated the JS Runtime:** The crash happens identically when using either Node.js v22 or Bun.
4. **Isolated the Wrangler Version:** Rolling back to previous versions of `wrangler` did not fix the issue.
5. **Cleared All State:** I have completely removed all `.wrangler` directories (both global and local) and reinstalled all `node_modules`.
6. **Checked Environmental Factors:**
* The issue persists even after disabling my system-wide proxy.
* The issue persists after temporarily disabling all antivirus/security software.

**Environment:**

版本 Windows 11 家庭中文版
版本号 24H2
安装日期 ‎2025/‎6/‎26
操作系统版本 26100.4484
体验 Windows 功能体验包 1000.26100.128.0

⛅️ wrangler 4.23.0, node v22.15.0, npm v11.4.2, bun v1.2.18

Image

1. Run `npx wrangler init hello-worker`.
2. `cd hello-worker`.
3. Run `npx wrangler dev --log-level debug`.

### Please provide any relevant error logs

```
--- 2025-07-04T13:45:13.989Z debug
🪵 Writing logs to "C:\Users\xuexu\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2025-07-04_13-45-13_808.log"
---

--- 2025-07-04T13:45:13.989Z log
Proxy environment variables detected. We'll use your proxy for fetch requests.
---

--- 2025-07-04T13:45:14.038Z log

Cloudflare collects anonymous telemetry about your usage of Wrangler. Learn more at https://github.com/cloudflare/workers-sdk/tree/main/packages/wrangler/telemetry.md
---

--- 2025-07-04T13:45:14.043Z debug
Metrics dispatcher: Posting data {"deviceId":"fc6ecee9-e5f8-4cf1-9fc8-f062638f049e","event":"wrangler command started","timestamp":1751636714043,"properties":{"amplitude_session_id":1751636714037,"amplitude_event_id":0,"wranglerVersion":"4.23.0","osPlatform":"Windows","osVersion":"Windows 11 Home China","nodeVersion":22,"packageManager":"npm","isFirstUsage":false,"configFileType":"jsonc","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"argsUsed":[],"argsCombination":"","command":"wrangler dev","args":{"xJsonConfig":true,"j":true,"latest":true,"noBundle":false,"remote":false,"r":false,"testScheduled":false,"xVectorizeBindToProd":false,"xImagesLocalMode":false}}}
---

--- 2025-07-04T13:45:14.059Z debug
.env file not found at ".env". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2025-07-04T13:45:14.086Z log

⛅️ wrangler 4.23.0
───────────────────
---

--- 2025-07-04T13:45:14.311Z debug
.env file not found at ".dev.vars". Continuing... For more details, refer to https://developers.cloudflare.com/workers/wrangler/system-environment-variables/
---

--- 2025-07-04T13:45:14.405Z debug
RemoteRuntimeController teardown beginning...
---

--- 2025-07-04T13:45:14.405Z debug
RemoteRuntimeController teardown complete
---

--- 2025-07-04T13:45:14.407Z log
⎔ Starting local server...
---

--- 2025-07-04T13:45:15.404Z error
✘ [ERROR] There was an access violation in the runtime.

On Windows, this may be caused by an outdated Microsoft Visual C++ Redistributable library.
Check that you have the latest version installed.
See https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist.

---

--- 2025-07-04T13:45:15.404Z debug
*** Received structured exception #0xc0000005: access violation; stack: 7fff04f6929f 7ff71bb12cca 7ff71bb12d93 7ff71bab13ac 7ff71bab1357 7ff71af77f1f 7ff71af78390 7ff71998385f 7ff71b103a4f 7ff71b10a976 7ff71b103f53 7ff71b10a976 7ff71b1018ec 7ff719971fc7 7ff71c2b1a7f 7fff2208e8d6 7fff2313c34b
---

--- 2025-07-04T13:45:15.407Z error
✘ [ERROR] There was an access violation in the runtime.

On Windows, this may be caused by an outdated Microsoft Visual C++ Redistributable library.
Check that you have the latest version installed.
See https://learn.microsoft.com/en-us/cpp/windows/latest-supported-vc-redist.

---

--- 2025-07-04T13:45:15.407Z debug
*** Received structured exception #0xc00000

05: access violation; stack: 7fff04f6929f 7ff71bb12cca 7ff71bb12d93 7ff71bab13ac 7ff71bab1357 7ff71af77f1f 7ff71af78390 7ff71998385f 7ff71b103a4f 7ff71b10a976 7ff71b103f53 7ff71b10a976 7ff71b1018ec 7ff719971fc7 7ff71c2b1a7f 7fff2208e8d6 7fff2313c34b
---

--- 2025-07-04T13:45:15.478Z debug
Error in ProxyController: Could not connect to InspectorProxyWorker
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
code: 'ERR_RUNTIME_FAILURE',
cause: undefined
}
---

--- 2025-07-04T13:45:15.479Z debug
=> Error contextual data: {
config: {
name: 'hello-worker',
config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
compatibilityDate: '2025-07-04',
compatibilityFlags: [],
complianceRegion: undefined,
entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
projectRoot: 'D:\\webProject\\hello-worker',
bindings: {},
migrations: [],
sendMetrics: undefined,
triggers: [],
env: undefined,
build: {
alias: undefined,
additionalModules: [],
processEntrypoint: false,
bundle: true,
findAdditionalModules: undefined,
moduleRoot: 'D:\\webProject\\hello-worker\\src',
moduleRules: [],
minify: undefined,
keepNames: undefined,
define: {},
custom: [Object],
format: 'modules',
nodejsCompatMode: null,
jsxFactory: 'React.createElement',
jsxFragment: 'React.Fragment',
tsconfig: undefined,
exports: [Array]
},
containers: undefined,
dev: {
auth: [AsyncFunction: auth],
remote: false,
server: [Object],
inspector: [Object],
origin: [Object],
liveReload: false,
testScheduled: false,
persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
registry: undefined,
bindVectorizeToProd: false,
multiworkerPrimary: undefined,
imagesLocalMode: false,
experimentalRemoteBindings: false,
enableContainers: true,
dockerPath: 'docker',
containerEngine: '//./pipe/docker_engine',
containerBuildId: '13b58346'
},
legacy: { site: undefined, enableServiceEnvironments: false },
unsafe: { capnp: undefined, metadata: undefined },
assets: undefined,
tailConsumers: []
},
bundle: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
Error in ProxyController: Failed to start ProxyWorker or InspectorProxyWorker
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
code: 'ERR_RUNTIME_FAILURE',
cause: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
=> Error contextual data: {
config: {
name: 'hello-worker',
config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
compatibilityDate: '2025-07-04',
compatibilityFlags: [],
complianceRegion: undefined,
entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
projectRoot: 'D:\\webProject\\hello-worker',
bindings: {},
migrations: [],
sendMetrics: undefined,
triggers: [],
env: undefined,
build: {
alias: undefined,
additionalModules: [],
processEntrypoint: false,
bundle: true,
findAdditionalModules: undefined,
moduleRoot: 'D:\\webProject\\hello-worker\\src',
moduleRules: [],
minify: undefined,
keepNames: undefined,
define: {},
custom: [Object],
format: 'modules',
nodejsCompatMode: null,
jsxFactory: 'React.createElement',
jsxFragment: 'React.Fragment',
tsconfig: undefined,
exports: [Array]
},
containers: undefined,
dev: {
auth: [AsyncFunction: auth],
remote: false,
server: [Object],
inspector: [Object],
origin: [Object],
liveReload: false,
testScheduled: false,
persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
registry: undefined,
bindVectorizeToProd: false,
multiworkerPrimary: undefined,
imagesLocalMode: false,
experimentalRemoteBindings: false,
enableContainers: true,
dockerPath: 'docker',
containerEngine: '//./pipe/docker_engine',
containerBuildId: '13b58346'
},
legacy: { site: undefined, enableServiceEnvironments: false },
unsafe: { capnp: undefined, metadata: undefined },
assets: undefined,
tailConsumers: []
},
bundle: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
Error in ProxyController: Failed to send message to InspectorProxyWorker: {"type":"reloadStart"}
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
code: 'ERR_RUNTIME_FAILURE',
cause: undefined
}
---

--- 2025-07-04T13:45:15.488Z debug
=> Error contextual data: {
config: {
name: 'hello-worker',
config: 'D:\\webProject\\hello-worker\\wrangler.jsonc',
compatibilityDate: '2025-07-04',
compatibilityFlags: [],
complianceRegion: undefined,
entrypoint: 'D:\\webProject\\hello-worker\\src\\index.js',
projectRoot: 'D:\\webProject\\hello-worker',
bindings: {},
migrations: [],
sendMetrics: undefined,
triggers: [],
env: undefined,
build: {
alias: undefined,
additionalModules: [],
processEntrypoint: false,
bundle: true,
findAdditionalModules: undefined,
moduleRoot: 'D:\\webProject\\hello-worker\\src',
moduleRules: [],
minify: undefined,
keepNames: undefined,
define: {},
custom: [Object],
format: 'modules',
nodejsCompatMode: null,
jsxFactory: 'React.createElement',
jsxFragment: 'React.Fragment',
tsconfig: undefined,
exports: [Array]
},
containers: undefined,
dev: {
auth: [AsyncFunction: auth],
remote: false,
server: [Object],
inspector: [Object],
origin: [Object],
liveReload: false,
testScheduled: false,
persist: 'D:\\webProject\\hello-worker\\.wrangler\\state',
registry: undefined,
bindVectorizeToProd: false,
multiworkerPrimary: undefined,
imagesLocalMode: false,
experimentalRemoteBindings: false,
enableContainers: true,
dockerPath: 'docker',
containerEngine: '//./pipe/docker_engine',
containerBuildId: '13b58346'
},
legacy: { site: undefined, enableServiceEnvironments: false },
unsafe: { capnp: undefined, metadata: undefined },
assets: undefined,
tailConsumers: []
},
bundle: undefined
}
---

--- 2025-07-04T13:45:15.489Z log

---

--- 2025-07-04T13:45:15.491Z error
✘ [ERROR] The Workers runtime failed to start. There is likely additional logging output above.

---

--- 2025-07-04T13:45:15.491Z debug
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48)
---

--- 2025-07-04T13:45:15.491Z log
If you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose
---

--- 2025-07-04T13:45:15.572Z debug
Error in LocalRuntimeController: Error reloading local server
MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
at #assembleAndUpdateConfig (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20871:13)
at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48)
at async #waitForReady (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:20946:5)
at async #onBundleComplete (D:\webProject\hello-worker\node_modules\wrangler\wrangler-dist\cli.js:174526:33)
at async Mutex.runWith (D:\webProject\hello-worker\node_modules\miniflare\dist\src\index.js:2197:48) {
code: 'ERR_RUNTIME_FAILURE',
cause: undefined
}
---

--- 2025-07-04T13:45:15.572Z debug
=> Error contextual data: undefined
---

--- 2025-07-04T13:45:17.300Z debug
Sentry: Capturing exception MiniflareCoreError [ERR_RUNTIME_FAILURE]: The Workers runtime failed to start. There is likely additional logging output above.
---

--- 2025-07-04T13:45:17.308Z debug
Metrics dispatcher: Posting data {"deviceId":"fc6ecee9-e5f8-4cf1-9fc8-f062638f049e","event":"wrangler command errored","timestamp":1751636717308,"properties":{"amplitude_session_id":1751636714037,"amplitude_event_id":1,"wranglerVersion":"4.23.0","osPlatform":"Windows","osVersion":"Windows 11 Home China","nodeVersion":22,"packageManager":"npm","isFirstUsage":false,"configFileType":"jsonc","isCI":false,"isPagesCI":false,"isWorkersCI":false,"isInteractive":true,"hasAssets":false,"argsUsed":[],"argsCombination":"","command":"wrangler dev","args":{"xJsonConfig":true,"j":true,"latest":true,"noBundle":false,"remote":false,"r":false,"testScheduled":false,"xVectorizeBindToProd":false,"xImagesLocalMode":false},"durationMs":3299,"durationSeconds":3.299,"durationMinutes":0.054983333333333335}}
---
```

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