---
title: allowsRunningApplicationSubstitution
framework: appkit
role: symbol
role_heading: Instance Property
path: appkit/nsworkspace/openconfiguration/allowsrunningapplicationsubstitution
---

# allowsRunningApplicationSubstitution

A Boolean value that indicates whether to use a running instance of an application even if it’s at a different URL.

## Declaration

```swift
var allowsRunningApplicationSubstitution: Bool { get set }
```

## Discussion

Discussion If an instance of an application is already running and is capable of opening the provided URLs, but the running instance is at a different URL, use the running application. This property defaults to true. Set this to false if you let the user select between specific versions of an application, or let them choose a particular installation.

## See Also

### Specifying app-related behaviors

- [activates](appkit/nsworkspace/openconfiguration/activates.md)
- [addsToRecentItems](appkit/nsworkspace/openconfiguration/addstorecentitems.md)
- [createsNewApplicationInstance](appkit/nsworkspace/openconfiguration/createsnewapplicationinstance.md)
- [hides](appkit/nsworkspace/openconfiguration/hides.md)
- [hidesOthers](appkit/nsworkspace/openconfiguration/hidesothers.md)