Blog Feature Image

Posted on July 2, 2024 | All

Case Study: Legacy Modernization: VB6 to .NET


This case study will explore a real-world example of legacy system modernization, focusing on transitioning from VB6 to .NET. It will cover the challenges faced during the migration process, the solutions implemented to overcome them, and the benefits realized post-migration.

The case study will provide insights into how Legacy VB6 Migration can improve performance, security, and scalability.


Visual Basic (VB), created by Microsoft in 1991, was widely used for enterprise applications. However, Microsoft abandoned VB in favor of the modern .NET Framework, with the final VB release being version 6 in 1998. Although Windows still supports core VB6 functionality, the VB6 IDE is no longer supported, making migration to .NET essential for many businesses.

The Imperative for Modernization

In today’s rapidly evolving technological landscape, modernizing legacy frameworks is not just beneficial—it’s essential for business survival and growth. Moving away from VB6 to .NET offers numerous advantages:

  • Future-Proofing: Stay relevant in a competitive market by leveraging cutting-edge technologies and frameworks.
  • Enhanced Security: Modern frameworks provide robust security features to protect against evolving cyber threats.
  • Talent Acquisition: Attract and retain top development talent who prefer working with modern technologies.
  • Ecosystem Integration: Seamlessly integrate with a vast ecosystem of modern tools, libraries, and cloud services.

Why .NET?

  • Rich Set of Classes: .NET offers comprehensive APIs for various business solutions, reducing the amount of code developers need to write.
  • Device Compatibility: .NET applications can run on various devices, from mobile phones to 64-bit servers.
  • Internet Integration: .NET provides robust support for Internet-aware technologies, crucial for modern business operations.
  • Developer Availability: It’s easier to find and retain .NET developers compared to VB6 specialists.
  • Ongoing Support: Microsoft continues to support .NET, ensuring ongoing updates and security patches.

Problem Statements:

  1. Obsolete Technology:
    • Causes: VB6 is outdated, leading to compatibility issues with modern operating systems, lack of support, and limited integration capabilities with new technologies.
    • Solution: Transitioning to .NET, which is actively supported and offers better integration and compatibility with current systems.
    • Data/Trends: According to a 2023 Gartner report, 60% of businesses are moving away from legacy systems due to increasing operational risks and costs associated with maintaining obsolete technologies.
  2. Security Vulnerabilities:
    • Causes:Legacy systems often have outdated security protocols, making them susceptible to modern cyber threats and attacks.
    • Solution: Migrating to .NET provides updated security features and regular patches, enhancing overall system security.
    • Data/Trends:A study by Cybersecurity Ventures in 2022 noted that companies with legacy systems are 40% more likely to experience a data breach compared to those using updated technology.
  3. Performance Bottlenecks:
    • Causes: Legacy systems like VB6 may not efficiently handle modern data loads or provide optimal performance, leading to slower processing times and decreased productivity.
    • Solution: Implementing .NET can significantly improve system performance through enhanced processing capabilities and better resource management.
    • Data/Trends:Performance benchmarking by TechRepublic in 2023 showed that .NET applications perform up to 50% faster than their VB6 counterparts.
  4. Limited Scalability:
    • Causes: VB6 systems are often rigid and not designed to scale with the growing needs of a business, hindering expansion and adaptation to new requirements.
    • Solution: .NET offers scalable architecture that can grow with the business, accommodating increasing user demands and data volumes.
    • Data/Trends:IDC’s 2022 report highlighted that businesses adopting scalable .NET solutions experienced a 35% increase in operational efficiency within the first year.
  5. High Maintenance Costs:
    • Causes:Maintaining legacy systems like VB6 can be costly due to the scarcity of skilled developers and the need for frequent fixes and patches.
    • Solution:Modernizing to .NET reduces maintenance costs by leveraging a larger pool of skilled developers and benefiting from ongoing updates and community support.
    • Data/Trends: According to a 2021 Forrester study, companies that modernized their legacy systems reported a 25% reduction in maintenance costs within two years.

How to Migrate to .Net?

  1. Migrate to Microsoft .NET:
    • Use automated tools like the Visual Basic Upgrade Wizard to move code to .NET, retaining functionality while adding new capabilities.
  2. Extend with Microsoft .NET:
    • Enhance the application with .NET while keeping the core VB6 application intact.
  3. Rewrite in Microsoft .NET:
    • Develop a new application in .NET, retaining domain knowledge but not the original code.
  4. Replace:
    • Find an alternative solution from an Independent Software Vendor (ISV) or outsource the development.
  5. Do Nothing:
    • If the application is stable and doesn’t require changes, no immediate action is necessary.

Case Study: ERP Migration from Legacy System to .NET


A complete ERP system implemented in a legacy VB6 framework needed to be migrated to a current framework to enhance scalability and usability. The objective was to ensure Visual Basic 6 Modernization.

Problem Statement with Legacy Code Migration

The existing ERP system faced several limitations:

  • Scalability: The application could not efficiently scale to meet growing business needs.
  • Database Flexibility: It lacked the capability to use multiple databases.
  • Cloud Integration: The system was not cloud-ready, limiting accessibility and modern functionality.

The solution was to migrate the ERP system to the .NET framework, resulting in a cloud-ready system. This VB6 to .NET Transformation enabled:

  • Cloud Availability: The new system is fully integrated with cloud services, providing better accessibility and scalability.
  • Web and Desktop Compatibility: Unlike VB6, .NET supports both web-based and desktop applications, offering greater flexibility.


The migration to the .NET framework provided significant tangible benefits, including:

Improved Performance

The new system achieved an average of 30-40% increase in processing speed, enhancing overall efficiency.

Note: Performance gains may vary depending on the complexity of the original application and optimization efforts during migration.

Enhanced Scalability

The system’s capacity to handle concurrent users increased by up to 50%, supporting business growth. This improvement was particularly noticeable in applications that were re-architected to take full advantage of .NET’s multithreading capabilities.

Reduced Maintenance Costs

Maintenance and support costs were reduced by approximately 25-30% due to the streamlined .NET environment and better resource utilization. Factors contributing to this reduction include improved tooling, a larger pool of skilled .NET developers, and more efficient debugging processes.

Cloud Integration

By leveraging cloud services in conjunction with the .NET migration, the company reduced infrastructure costs by an average of 20-25%. This provided greater flexibility and remote accessibility, with the extent of savings varying based on the specific cloud services adopted and the previous on-premises infrastructure costs.

The CIG Advantage

Choosing the right partner for your modernization journey is crucial. CI Global stands out by offering:

  • Proven Expertise: Years of experience in successfully migrating VB6 applications to .NET and other modern frameworks.
  • Tailored Strategies: Custom migration approaches designed to meet your specific business needs and goals.
  • Minimal Disruption: Carefully planned and executed migrations to ensure business continuity.
  • Comprehensive Support: End-to-end assistance, from initial assessment to post-migration optimization.
  • Innovation Focus: Not just migration, but transformation—reimagining your applications for the digital age.

CI Global: Your VB6 to .NET Migration Services Partner

It is vital to modernize the frameworks and step away from VB6. Stay relevant by migrating to .NET, and leverage modern technologies to stay ahead of the curve.

With the right strategy and approach, the VB6 migration process can be efficient and seamless. By partnering with CI Global, enterprises can:

  • Effectively overcome associated challenges
  • Transition smoothly to modern frameworks
  • Realize significant long-term benefits in performance, scalability, and cost-efficiency

CI Global specializes in creating digital transformation experiences for our clients. To start migrating your VB6 applications to .NET Core and other modern frameworks, contact us today!