Abstract
The implemented enterprise systems cannot keep being used automatically for a long time without maintenance. Maintenance is indispensable for every enterprise system to adapt to changes in business environment and new rules in the operational phase. Though it is important for every user organization to design the process of the maintenance management, the fact is that the studies which are focusing on the maintenance activity are a little. This study classifies the individual maintenance tasks based on two perspectives of "content of operation" and "factor of occurrence". In addition, this study identifies the maintenance trends and the characteristic of the investigated enterprise system, based on the number and the workload of each task.
