Comment #5 on issue 3575 by guillerm...@gmail.com: [Failing Tests] Package Monticello leaves Obsolete class after tests http://code.google.com/p/pharo/issues/detail?id=3575 Actually, the Obsolete class is AnObsoleteAutoGeneratedClassForTestingSystemChanges. I dived a little into the tests. The test that is creating the obsolete class is: ChangeHooksTest>>testClassCommentedEvent self systemChangeNotifier notify: self ofAllSystemChangesUsing: #classCommentedEvent:. generatedTestClass comment: self commentStringForTesting. self checkForOnlySingleEvent The other tests of this class work just well. I dived into TraitDescription>>comment: to see if it keeps references to the class or an instance, but I didn't found anything significant...