Enterprise Resource Planning (ERP) has become essential as a result of the acceleration of digitalization and the necessity of companies to integrate their business processes. ERP has various models depending on the system scalability e.g. for small and medium entities (SME) and enterprises. PT Gamma is one of the food and beverage chains with massive growth in Indonesia which uses Oracle NetSuite (ERP for SME). Due to non-scalability, management decided to migrate to the enterprise ERP not so long after usage. This research follows the roadmap of six sigma (DMAI: define, measure, analyze and improve): (1) define the root cause of non-optimum implementation of ERP using in-depth structured interviews with key users; (2) measure the sigma value based on projects document; (3) analyze and code interview result to define which Critical Success Factors (CSFs) are more dominants then distribute questionnaire (1-10 scale) to define the Risk Priority Number (RPN); and (4) formulate solutions for dominant issues and ask key users for verification. Sigma value showed 3.234 (moderate level) through calculations number of outstanding issues compared to all issues rose during January-August 2022. Dominant factors identified by decision-makers are technological (71%) and organizational factors (19%), meanwhile supporting users are technological (42%), organizational (25%) and external party factors (17%). Suggestions for management are the alignment of ERP selection with the long-term company’s strategic vision, avoiding over-customization, performing regular checkpoints, and selecting the best consultant for re-migration. Suggestions for further research are a longer research period and a more extensive method of six-sigma.