Trouble creating Security-Scoped Bookmark

I'm converting my Lion app to use the App Sandbox. I'm trying to make use of the security-scoped bookmarks feature introduced in 10.7.3 to allow persistent access to a folder. The code I have below returns a nil bookmark, and produces the following log message: `XPC couldn't look up the Mach service for scoped bookmarks agent`. I set the `User Selected File Access` entitlement to `Read/Write Access`, and also tried with and without the surrounding `..AccessingSecurityScopedResource` calls. I think I'm doing everything right according to the documentation, so I'd appreciate any pointers. The code was working to retrieve a plain URL before I began sandboxing the app. ``` NSOpenPanel *openPanel = [NSOpenPanel openPanel]; [openPanel setCanChooseFiles:NO]; [openPanel setCanChooseDirectories:YES]; [openPanel setAllowsMultipleSelection:NO]; NSInteger result = [openPanel runModal]; if( result == NSFileHandlingPanelCancelButton ) { return; } NSArray *urls = [openPanel URLs]; if( urls != nil && [urls count] == 1 ) { NSURL *url = [urls objectAtIndex:0]; NSData *bookmark = nil; NSError *error = nil; bookmark = [url bookmarkDataWithOptions:NSURLBookmarkCreationWithSecurityScope includingResourceValuesForKeys:nil relativeToURL:nil // Make it app-scoped error:&error]; if (error) { NSLog(@"Error creating bookmark for URL (%@): %@", url, error); [NSApp presentError:error]; } NSLog(@"bookmark: %@", bookmark); } ``` Update (x3) Now that I got it working, I can verify that the calls to `-startAccessingSecurityScopedResource` and `-stopAccessingSecurityScopedResource` are not necessary in the code above, since the Powerbox grants access to the resource after the user selects it in the `NSOpenPanel`. If you're creating a bookmark from another security-scoped URL, such as making a document-scoped bookmark from an app-scoped bookmark created in another app session, then you need to get access to the file first.