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# WCError

A structure that contains Watch Connectivity error information.

```
struct WCError
```

## Topics

### Accessing Error Data

### Accessing the Error Domain

### Understanding Error Codes

[`genericError`](/documentation/WatchConnectivity/WCError/genericError)

An error that occurs when there is an unknown problem.

[`sessionNotSupported`](/documentation/WatchConnectivity/WCError/sessionNotSupported)

An error indicating that the current device doesn’t support the use of session objects.

[`sessionMissingDelegate`](/documentation/WatchConnectivity/WCError/sessionMissingDelegate)

An error indicating that the WatchKit extension doesn’t have a valid extension delegate to process events.

[`sessionNotActivated`](/documentation/WatchConnectivity/WCError/sessionNotActivated)

An error indicating that the other device doesn’t have an active session.

[`deviceNotPaired`](/documentation/WatchConnectivity/WCError/deviceNotPaired)

An error indicating that the current device doesn’t have a paired counterpart.

[`watchAppNotInstalled`](/documentation/WatchConnectivity/WCError/watchAppNotInstalled)

An error indicating that the Watch app isn’t an installed app on the user’s Apple Watch.

[`notReachable`](/documentation/WatchConnectivity/WCError/notReachable)

An error indicating that the counterpart app isn’t reachable.

[`invalidParameter`](/documentation/WatchConnectivity/WCError/invalidParameter)

An error indicating that a parameter is invalid.

[`payloadTooLarge`](/documentation/WatchConnectivity/WCError/payloadTooLarge)

An error indicating an attempt to send an item that exceeds the maximum size limit.

[`payloadUnsupportedTypes`](/documentation/WatchConnectivity/WCError/payloadUnsupportedTypes)

An error indicating that a dictionary contains nonproperty list types.

[`messageReplyFailed`](/documentation/WatchConnectivity/WCError/messageReplyFailed)

An error that occurs when the system can’t return the reply.

[`messageReplyTimedOut`](/documentation/WatchConnectivity/WCError/messageReplyTimedOut)

An error that occurs when the counterpart app doesn’t return a reply in time.

[`fileAccessDenied`](/documentation/WatchConnectivity/WCError/fileAccessDenied)

An error indicating that the system can’t transfer a file because it is inaccessible.

[`deliveryFailed`](/documentation/WatchConnectivity/WCError/deliveryFailed)

An error that occurs when the system can’t deliver the payload.

[`insufficientSpace`](/documentation/WatchConnectivity/WCError/insufficientSpace)

An error indicating that there isn’t enough space on the receiving side to store the data.

[`sessionInactive`](/documentation/WatchConnectivity/WCError/sessionInactive)

An error indicating that the session is inactive.

[`transferTimedOut`](/documentation/WatchConnectivity/WCError/transferTimedOut)

An error that occurs when the transfer reaches the timeout limit before it completes.

[`companionAppNotInstalled`](/documentation/WatchConnectivity/WCError/companionAppNotInstalled)

An error indicating that the companion hasn’t installed the app.

[`watchOnlyApp`](/documentation/WatchConnectivity/WCError/watchOnlyApp)

An error indicating that the app is a watch-only app.

### Comparing Errors

### Enumerations

[`WCError.Code`](/documentation/WatchConnectivity/WCError/Code)

Constants for errors during a session.


---

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