According to a survey by Gartner, over 70% of companies that attempted to modernize their mainframe systems in the first half of 2026 failed to achieve their objectives. The research indicates that excessive reliance on generative AI has been a contributing factor to these project failures.
Over 70% of Mainframe Modernization Projects Fail, Driven by Overreliance on Generative AI
PLUS ULTRA by Amenoyomi
The shift from mainframes to cloud-based environments or other modern infrastructures is often complicated by the presence of legacy systems, such as COBOL-based applications and ERP systems. The report highlights that relying too heavily on generative AI during these critical system migrations has contributed to project failures.
PLUS ULTRAby Amenoyomi
The high failure rate stems from a fundamental misunderstanding of the role generative AI plays in legacy system migration. While AI is effective at translating COBOL syntax into modern languages or adapting code to new specifications, it cannot decipher the underlying "intent"—the specific business logic and original purpose that the legacy code was designed to implement.
When companies rely solely on AI for conversion, they risk creating "black boxes" where the new system's behavior is accepted without a deep understanding of the original business requirements. Because the AI cannot explain the "why" behind a process, the resulting system may appear functional but exhibit unintended behaviors that are difficult to detect. This gap makes rigorous verification nearly impossible, often leading to critical errors and significant project delays.
Consequently, successful modernization requires a clear division of labor. Humans must perform the intellectual work of deciphering legacy business logic and designing the new system architecture, while generative AI is utilized as a tool to increase the efficiency of the technical transition.
Sources
- 脱メインフレーム、7割超が失敗 背景に「生成AIへの過信」 2026年度上半期システム刷新記事ランキング (ITmedia AI+, 2026-09-22)