Been encountering this error a lot in my OS X using swift:
\"This application is modifying the autolayout engine from a background thread, which can
It could be something as simple as setting a text field / label value or adding a subview inside a background thread, which may cause a field's layout to change. Make sure anything you do with the interface only happens in the main thread.
Check this link: https://forums.developer.apple.com/thread/7399