Assemblies: System.Threading.Tasks (in System.Threading.Tasks.dll)
mscorlib (in mscorlib.dll)
Tasks that throw unhandled exceptions store the resulting exception and propagate it wrapped in a AggregateException in calls to Wait or in accesses to the property. Any exceptions not observed by the time the task instance is garbage collected will be propagated on the finalizer thread. For more information and an example, see Exception Handling (Task Parallel Library).