Have your Qt Quick applications been on the crashed bus since you upgraded or installed Qt 5.6.1? The problem has been solved with the latest Qt 5.6.1-1 release.
The problem occurs in some Qt Quick applications when you have more than 64 components and don’t instantiate from all of them and try to do so later in your application processes. These include qml and js files.
How to Fix the Bug with the Qt 5.6.1-1 Release
We highly advise you if you haven’t already to get the update that fixes the aforementioned issue. This can be done using the maintenance tool that comes with the Qt SDK or getting the offline packages from the Qt Account portal for commercial users or the Qt download page.