The problem is that the data folder isn't in the same Application GUID as the app bundle. Eg:
NSLog(@"App Path: %@", [NSBundle mainBundle].resourcePath);
NSLog(@"App data: %@", NSSearchPathForDirectoriesInDomains(NSLibraryDirectory, NSUserDomainMask, YES));
App Path: /Users/richard/Library/Developer/CoreSimulator/Devices/FEC3CDE4-8B8F-41DC-923D-4B4433BEB101/data/Containers/Bundle/Application/ 1D0C21A3-B259-4BD5-AFBA-303412AE2092/'app name'.app
App data: /Users/richard/Library/Developer/CoreSimulator/Devices/FEC3CDE4-8B8F-41DC-923D-4B4433BEB101/data/Containers/Data/Application/ 5561FE4D-E9BD-47BF-B175-B56C959AC377/Library
which is really annoying - so as soon as you have more than a couple of apps on your simulator then finding the Data folder from just the app bundle path is horrible. And the contents of the Data application folder doesn't help as they all have the same contents:
Such fun.... I had a problem with SimPholders crashing a lot recently but updating to the latest version has fixed it fortunately.