---
title: backingStoreIdentity
framework: fileprovider
role: symbol
role_heading: Instance Property
path: fileprovider/nsfileproviderdomain/backingstoreidentity
---

# backingStoreIdentity

A unique identifier for the backing store used by the system.

## Declaration

```swift
var backingStoreIdentity: Data? { get }
```

## Discussion

Discussion Changes to this identifier indicate that the system has dropped its backing store and is creating a new one. The system may create a new backing store if the old store becomes corrupted. The file provider extension can also request a new backing store by calling reimportItems(below:completionHandler:). While rebuilding the backing store, the system invalidates any extension instances associated with the domain. As a result, the system guarantees that the backingStoreIdentity remains stable throughout the lifetime of an NSFileProviderReplicatedExtension instance. note: This property is only available on file provider extensions based on the NSFileProviderReplicatedExtension protocol.

## See Also

### Accessing data

- [displayName](fileprovider/nsfileproviderdomain/displayname.md)
- [identifier](fileprovider/nsfileproviderdomain/identifier.md)
- [isReplicated](fileprovider/nsfileproviderdomain/isreplicated.md)
- [pathRelativeToDocumentStorage](fileprovider/nsfileproviderdomain/pathrelativetodocumentstorage.md)
- [isHidden](fileprovider/nsfileproviderdomain/ishidden.md)
- [userEnabled](fileprovider/nsfileproviderdomain/userenabled.md)
- [isDisconnected](fileprovider/nsfileproviderdomain/isdisconnected.md)
- [supportsSyncingTrash](fileprovider/nsfileproviderdomain/supportssyncingtrash.md)
- [userInfo](fileprovider/nsfileproviderdomain/userinfo.md)
- [volumeUUID](fileprovider/nsfileproviderdomain/volumeuuid.md)