<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 13.0.0 -",
    "macOS: 13.0.0 -",
    "visionOS: 1.0.0 -",
    "watchOS: 2.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "HealthKit",
  "identifier" : "/documentation/HealthKit/HKError/Code/errorAnotherWorkoutSessionStarted",
  "metadataVersion" : "0.1.0",
  "role" : "Case",
  "symbol" : {
    "kind" : "Case",
    "modules" : [
      "HealthKit"
    ],
    "preciseIdentifier" : "c:@E@HKErrorCode@HKErrorAnotherWorkoutSessionStarted"
  },
  "title" : "HKError.Code.errorAnotherWorkoutSessionStarted"
}
-->

# HKError.Code.errorAnotherWorkoutSessionStarted

Another app started a workout session.

```
case errorAnotherWorkoutSessionStarted
```

## Discussion

This error occurs whenever a second workout session is started. Apple Watch only runs one workout session at a time. If the user begins a second workout session in a different app, the original session receives this error message and then ends. The second session then starts.

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)