---
title: NSUnknownUserInfoKey
framework: objectivec
role: article
role_heading: Article
path: objectivec/nsunknownuserinfokey
---

# NSUnknownUserInfoKey

The key for which the key value coding operation failed.

## See Also

### Constants

- [NSTargetObjectUserInfoKey](objectivec/nstargetobjectuserinfokey.md)