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  "title" : "NSError userInfo Dictionary Keys"
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# NSError userInfo Dictionary Keys

Keys in the userInfo dictionary of an `NSError` object when certain NSURL methods return an error.

## Topics

### Constants

[`static let keysOfUnsetValuesKey: URLResourceKey`](/documentation/Foundation/URLResourceKey/keysOfUnsetValuesKey)

Key for the resource properties that have not been set after the [`setResourceValues(_:)`](/documentation/Foundation/NSURL/setResourceValues(_:)) method returns an error, returned as an array of `NSString` objects.


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