---
title: NSMergePolicyType.errorMergePolicyType
framework: coredata
role: symbol
role_heading: Case
path: coredata/nsmergepolicytype/errormergepolicytype
---

# NSMergePolicyType.errorMergePolicyType

The default merge policy for all managed object contexts.

## Declaration

```swift
case errorMergePolicyType
```

## Discussion

Discussion If a save fails because of conflicting objects, you can find the IDs of those objects in error’s userInfo dictionary. Use the NSInsertedObjectsKey and NSUpdatedObjectsKey keys to extract the object IDs.

## See Also

### Policies

- [NSMergePolicyType.mergeByPropertyStoreTrumpMergePolicyType](coredata/nsmergepolicytype/mergebypropertystoretrumpmergepolicytype.md)
- [NSMergePolicyType.mergeByPropertyObjectTrumpMergePolicyType](coredata/nsmergepolicytype/mergebypropertyobjecttrumpmergepolicytype.md)
- [NSMergePolicyType.overwriteMergePolicyType](coredata/nsmergepolicytype/overwritemergepolicytype.md)
- [NSMergePolicyType.rollbackMergePolicyType](coredata/nsmergepolicytype/rollbackmergepolicytype.md)