What is an incident in IT services?

The official ITIL 4 definition of an incident is an unplanned interruption to a service or a reduction in the quality of a service. This definition focuses on the negative impact on the user or business operations as experienced through the service. The primary goal of incident management is to restore normal service operation as quickly as possible and minimize the adverse impact on business operations, ensuring that the best possible levels of service quality and availability are maintained.

A. This is the definition of an 'event,' which is any change of state that has significance for the management of a configuration item or IT service.

C. This is the definition of a 'problem,' which is a cause, or potential cause, of one or more incidents.

D. This describes a vulnerability or a 'known error,' which is a problem that has a documented root cause and a workaround.

1. AXELOS. (2019). ITIL® 4 Foundation, ITIL 4 Edition. TSO (The Stationery Office). Glossary, p. 221. The definition is explicitly stated as "An unplanned interruption to a service, or reduction in the quality of a service."

2. AXELOS. (2020). ITIL® 4 Practice Guide: Incident Management. TSO (The Stationery Office). Section 2.1, "Purpose and description," reiterates this core definition.