A bug or problem that occurs during execution of an application is detected and a time at which the problem occurred is stored. An enhanced copy of the application is restored from before the time at which the problem occurred, and the enhanced copy of the application is run. If the problem is reproduced, the application is paused. If the problem is not reproduced, restoration of the enhanced copy, running of the enhanced copy and detection of the problem are repeated for a pre-designated number of times.