cypress: Cannot find unclaimed instance for spec

Our engineering team has released a fix for this issue - of seeing the Cannot find unclaimed instance for spec error when running in Windows OS’s. This fix should be immediate and not require a new version of Cypress.

Please comment here or open a new issue if you continue to see this issue on any new runs that are recorded to the Dashboard.

I’m still facing this issue in the latest version of cypress (5.0.0) on Windows. Here is the full log with debug enabled if it helps:

2020-08-21T07:43:14.970Z cypress:server:run formatting Node version. { version: '12.14.1', path: undefined }
  ┌────────────────────────────────────────────────────────────────────────────────────────────────┐
  │ Cypress:    5.0.0                                                                              │
  │ Browser:    Chrome 84 (headless)                                                               │
  │ Specs:      1 found (my-app\my_tests.spec.js)                                   │
  │ Searched:   cypress\integration\my-app\my_tests.spec.js                         │
  │ Params:     Tag: false, Group: false, Parallel: false                                          │
  │ Run URL:    https://dashboard.cypress.io/projects/td8e9s/runs/11                               │
  └────────────────────────────────────────────────────────────────────────────────────────────────┘

2020-08-21T07:43:14.970Z cypress:server:record before spec run { spec: { name: 'my-app\\my_tests.spec.js', relative: 'cypress\\integration\\my-app\\my_tests.spec.js', absolute: 'C:/JenkinsHome/workspace/PolicyCenter10Jenkins_master/cypress/integration/my-app/my_tests.spec.js', specType: 'integration' } }
2020-08-21T07:43:14.985Z cypress:server:api request to url: POST https://api.cypress.io/runs/9583660c-c890-44d4-8fa8-26c68c5335ce/instances with params: {"body":{"spec":"cypress\\integration\\my-app\\my_tests.spec.js","groupId":"win32-Chrome-84-93c69e07ce","machineId":"c224efa7-9b3a-4ddf-8c61-11f89e38f2fb","platform":{"osCpus":[{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":5851593,"nice":0,"sys":2067515,"idle":3769855093,"irq":149953}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":8712859,"nice":0,"sys":1822750,"idle":3767238375,"irq":14343}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":9124109,"nice":0,"sys":2004375,"idle":3766645500,"irq":13875}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":7558437,"nice":0,"sys":1720734,"idle":3768494812,"irq":13156}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":6291125,"nice":0,"sys":1436562,"idle":3770046296,"irq":9562}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":6841437,"nice":0,"sys":2701609,"idle":3768230937,"irq":14765}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":6250609,"nice":0,"sys":1780515,"idle":3769742843,"irq":11375}},{"model":"Intel(R) Xeon(R) CPU E5-2686 v4 @ 2.30GHz","speed":2300,"times":{"user":5728078,"nice":0,"sys":1528203,"idle":3770517687,"irq":13453}}],"osName":"win32","osMemory":{"free":19789500416,"total":34359328768},"osVersion":"6.3.9600","browserName":"Chrome","browserVersion":"84.0.4147.135"}},"headers":{"x-route-version":"5","x-os-name":"win32","x-cypress-version":"5.0.0"}} and token: undefined
2020-08-21T07:43:14.985Z cypress:network:agent addRequest called { isHttps: true, href: 'https://api.cypress.io/runs/9583660c-c890-44d4-8fa8-26c68c5335ce/instances' }
2020-08-21T07:43:14.985Z cypress:network:agent got family { family: 4, href: 'https://api.cypress.io/runs/9583660c-c890-44d4-8fa8-26c68c5335ce/instances' }
2020-08-21T07:43:15.079Z cypress:server:record failed creating instance { stack: 'StatusCodeError: 400 - {"message":"Cannot find unclaimed instance for spec: cypress\\\\integration\\\\my-app\\\\my_tests.spec.js"}\n' + '    at new StatusCodeError (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\request-promise-core\\lib\\errors.js:32:15)\n' + '    at Request.plumbing.callback (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\request-promise-core\\lib\\plumbing.js:104:33)\n' + '    at Request.RP$callback [as _callback] (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\request-promise-core\\lib\\plumbing.js:46:31)\n' + '    at Request.self.callback (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\@cypress\\request\\request.js:185:22)\n' + '    at Request.emit (events.js:223:5)\n' + '    at Request.<anonymous> (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\@cypress\\request\\request.js:1156:10)\n' + '    at Request.emit (events.js:223:5)\n' + '    at IncomingMessage.<anonymous> (C:\\Users\\Administrator\\AppData\\Local\\Cypress\\Cache\\5.0.0\\Cypress\\resources\\app\\packages\\server\\node_modules\\@cypress\\request\\request.js:1078:12)\n' + '    at Object.onceWrapper (events.js:312:28)\n' + '    at IncomingMessage.emit (events.js:228:7)\n' + '    at endReadableNT (_stream_readable.js:1185:12)\n' + '    at processTicksAndRejections (internal/process/task_queues.js:81:21)\n' }
Warning: We encountered an error talking to our servers.

This run will not be recorded.

This error will not alter the exit code.

StatusCodeError: 400

{
  "message": "Cannot find unclaimed instance for spec: cypress\\integration\\my-app\\my_tests.spec.js"
}