Error when building the solution

[Wizard2003]

When building the solution all classes with attribute NotifyObservedReferenceChanged or NotifyObservedCollectionChanged have errors like:

Conflicting aspects on "PostSharp.NotifyPropertyChanged.Tests.NotifyObservedReferenceChangedAttribute_Tests.InterfaceObservingClass": 'Initialization of Aspect PostSharp.NotifyPropertyChanged.NotifyObservedReferenceChangedAttribute' must be followed by a transformation thatis derived from PostSharp.NotifyPropertyChanged.NotifyPropertyChangedAttribute.