The research was carried out in a large enterprise. There is a large amount of self-developed software. A problem with the software development process was noticed. The motivation for the research was a good understanding of the existing problem and the usage of findings in the form of a problem resolution in the future. The main idea was to reveal all the reasons for the problem. Good research is reliable and may be fundamental for future changes in the enterprise. The Ishikawa diagram is rarely used in the analysis of the process in the IT sector. However, often usage of the mentioned technique by scientists in other fields of science is visible. This article can be helpful for other researchers or specialists to make a decision if the Ishikawa diagram is suitable for their research. The most important characteristics that the Ishikawa diagram can provide are the comprehensive approach to the issue under consideration and the high effectiveness, including simplicity. Using the Ishikawa diagram may bring great benefits with minimal effort. Besides, the accuracy of the analysis was also a significant benefit. Indicated problems occur in five areas. Resolutions for four of them are presented in the publication. Awareness of the last problem is raised, but it needs further investigation.