Abstract: A method and a task scheduler for canceling a task in a computer system, wherein the task scheduler manages a plurality of tasks using at least one task queue. The task scheduler is arranged to free resources assigned to a cancelled task of the plurality of tasks when the cancelled task reaches the top of any of the at least one task queue. The method comprises steps of identifying a task from the plurality of tasks as a cancelled task, actively prioritizing the identified task to the top of its corresponding task queue and allowing the task scheduler to free resources assigned to the identified task. Optionally, the step of prioritizing may further comprises steps of setting a NextExecution parameter of the identified task to a value near zero and of notifying a memory garbage collector associated to the task scheduler that resources need to be freed.