Sandboxed Mac app exhausting security scoped URL resources

Question

I am developing a Mac application that prompts the user for files using the NSOpenPanel. The application is sandboxed (testing on OSX 10.9.4). I noticed that if I open a large a

Answer 1

The behavior you experience is because the security scoped resources are limited:

NSURL - (BOOL)startAccessingSecurityScopedResource tells

If sufficient kernel resources are leaked, your app loses its ability to add file-system locations to its sandbox...

The current limit is roughly what you experienced. See: What are the current kernel resource limits on security-scoped bookmarks?

To prevent it:

• only start accessing those SSBs you need at a given time and subsequently stop accessing them
• start access not files but enclosing folders: ask the user not to choose files but a full folder. This will grant you access to the whole tree beneath that directory
• on draggingEntered: show a NSOpenPanel with the enclosing directory(ies) to grant access