Society is based on knowledge and the availability thereof. Access to knowledge empowers people, and organizations must reuse knowledge to be competitive. The right knowledge to the right person at the right time is important for success, and IT plays an important role in order to achieve this goal, for example in the form of Electronic Knowledge Repositories (EKR). The success of an EKR depends on what is stored therein, and the ability to capture the right knowledge is hence a key aspect. This, however, is a complex issue. The goal of this paper is to identify and describe different types of knowledge loss, seven of which have been identified and characterized. As an example, one knowledge loss shows that not all knowledge can be stored, and critical knowledge elements may therefore be lost when attempting to store it. Some knowledge loss may be desirable, since an organization should not want to store everything. The results contribute to capturing the right knowledge, and hence to successful EKR. The results thus contribute to elevating the competitive power of an organization.