In information technology, the observer effect is the impact on the behaviour of a computer process caused by the act of observing the process while it is running.
Furthermore, the act of viewing the file while the process is running could cause an I/O error in the process, which could, in turn, cause it to stop.
The observer effect could either have a positive or negative impact on the computer process behaviour.
A positive impact can be software bugs, also known as Heisenbugs, which diminish or change their negative behavior when observation mechanisms, such as debugging, are enabled.
Such bugs usually create extra difficulties in being isolated.