Transforming an old Microsoft Access application into a modern web application is complex and challenging. Many organisations must upgrade their legacy systems to meet contemporary scalability, performance, and user experience requirements. Here are some of the most common challenges and possible solutions when rewriting old Access applications.
Challenges when migrating from Microsoft Access
Preservation of business logic
One of the biggest challenges when rewriting an old application in Microsoft Access is preserving the existing business logic. Access applications can contain complex macros and Visual Basic for Applications (VBA) code tightly integrated with the database. Extracting and translating this logic into a modern language such as C# or VB.NET requires careful analysis and planning.
Data integrity and migration
Access databases are often used to store critical business information. During a rewrite, it is essential to ensure that all data is migrated correctly and data integrity is maintained. This may involve converting data to a different format or structure, which can be complicated and time-consuming.
Have a backup if you intend to use the same database even after the migration. If the old Access application is used during development, a copy of the database can be used when developing the web version. The database may contain personal data, so you may want to pseudo-anonymise it. If you want to restructure the database instead, creating a conversion programme that can be used later when migrating data to the new web application is essential.
Scalability and performance
Microsoft Access is not designed to handle large amounts of data or many simultaneous users. When rewriting an application to a web application, choosing an architecture that can scale up to handle increasing load and user numbers is necessary. This may mean implementing a new database solution, such as MS SQL or a NoSQL database, and optimising the application’s performance.
User experience and interface
Access applications often have simple and limited user interfaces. A modern web application requires a more sophisticated and user-friendly interface. This means designing new UI components and using modern front-end technologies such as React, Angular or Vue to improve the user experience.
Broader accessibility
Microsoft Access applications are usually designed for use within a local network (intranet), limiting access to users on specific organisational computers. On the other hand, modern web applications can be made available over the Internet using any web browser. This allows users to access the application anywhere with an internet connection and on different devices, including desktops, laptops, tablets, and mobiles.
Solutions to overcome these challenges
Analyse and plan carefully
To ensure a smooth transition, a thorough analysis of the existing Access application is essential. Document all business logic, database structures, and user flows. Create a detailed plan for how each application part will be rewritten and migrated.
Use modern .NET technology.
C#.NET is an excellent choice for rewriting the business logic of a modern web application. Using ASP.NET Core, you can create a scalable, high-performance backend that can handle large amounts of data and many concurrent users. ASP.NET MVC and Web API can be used to build structured and modular applications.
Implement a robust database solution.
Choosing a robust database solution is essential for managing data integrity and migration. MS SQL Server offers advanced data storage and management capabilities, making it a good choice for most web applications. Use tools like ADO.NET and Entity Framework to interact easily with the database and ensure proper data transfer.
Improve the user interface.
To create a user-friendly and responsive interface, use modern front-end technologies like HTML5, CSS3, and TypeScript and frameworks like React, Angular, or Vue. Bootstrap can be used to create stylish and mobile-friendly user interfaces quickly. Focus on improving the user experience by making the interface intuitive and easy to use.
Ensure performance and scalability.
Implement caching, asynchronous operations, and load-balancing solutions to ensure your application can scale up to meet future needs. Cloud services such as Microsoft Azure or AWS can be exploited for their scalable infrastructures and services. In addition, you should prioritise security measures to protect your application and user data from security vulnerabilities. This is especially true when the database contains personal data, as the GDPR requires data protection by design and default. Here is another article on migrating to the cloud.
Test and validate
Finally, extensive testing of the new application must be conducted before it is launched. Validate that all business logic works as expected, that data is migrated correctly and that the user experience is improved. Automate testing tools and perform manual tests to ensure the application is stable and reliable.
Training and support for users
Transitioning to a new system often requires user training to ensure existing users can use the new application effectively. Adequately designed web applications are usually more intuitive and, therefore, easier to use than traditional applications. However, this does not mean that training is not needed. Providing comprehensive training and support documentation can ease the transition for end users.
To summarise
By carefully planning and using modern technologies, you can successfully transform an old application written in Microsoft Access into a modern web application that meets today’s performance, security, scalability and user experience requirements.
Do you need help?
If you need help migrating from Microsoft Access, don’t hesitate to contact us at Gislen Software. We have the expertise and experience to ensure a smooth and efficient update process. Whether you face technical challenges or need strategic guidance, we are here to help you achieve your goals. Contact us today to discuss how we can support your migration from Microsoft Access!
Do we always need a full rewrite to move away from Microsoft Access?
No. A full rewrite is one option, but it is not always the best one. Depending on the size, risk profile, and future needs of the system, you may be better served by a phased rebuild, a hybrid approach, a rehost/bridge step, or even replacing the solution with an off-the-shelf product. A credible plan starts with choosing the right path, not with committing to “rewrite everything”.
What are the biggest risks when modernising an Access application?
The biggest risks are usually not technical. They are hidden business rules, uncertain scope, data quality issues, operational disruption, and user adoption. Access systems often contain logic spread across forms, macros, reports, queries and VBA, and much of it may not be documented. The safest projects reduce uncertainty early and deliver in phases.
How do you preserve the business logic that lives in forms, macros and VBA?
We treat the Access application as a description of real workflows, not as a specification. We map key flows, capture validations and exceptions, and document “why” behind behaviours. We also validate with users using walkthroughs, prototypes, and scenario-based checks so the modern system behaves correctly before it replaces Access.
Can we run the Access application in parallel while the web system is being built?
Yes, and in many cases we recommend it. Parallel running reduces business disruption and allows careful migration workflow by workflow. It also gives users confidence because they can compare outcomes and confirm that the new system matches the old behaviour before Access is retired.
How do you handle data migration without losing integrity?
We start with data profiling to identify duplicates, missing values, inconsistent references and “creative” field usage. We then design a repeatable migration approach rather than a one-off export/import. For development and testing, we normally use a safe copy of the database and, where personal data is involved, we can pseudonymise datasets to reduce risk.
What database do you typically use when moving away from Access?
For many modernisations, SQL Server is a good fit because it supports concurrency, performance, and robust integrity controls. The right choice depends on the workload, reporting needs, and future integration plans. The key point is to move to a database designed for multi-user systems and long-term maintenance.
How do you approach security and compliance beyond just “GDPR”?
Modern systems typically need role-based access control (RBAC), least-privilege permissions, secure authentication (often SSO and MFA where appropriate), and audit logs for traceability. We also design safe test environments and apply data minimisation principles. If data residency matters (for example UK/EU separation), we plan for it upfront rather than retrofitting later.
Can AI help with modernising an Access system?
Yes, in specific ways. AI can accelerate analysis and documentation of VBA, assist with mapping data models, and help generate test cases and regression checks. However, AI does not replace architecture decisions, security judgement, or domain understanding. Used well, it speeds up discovery and quality work; it should not be treated as an automated rewrite button.
How do you avoid “big bang” rewrites that overrun time and budget?
We plan phased delivery with early validation. That usually means starting with discovery, mapping the riskiest workflows, and delivering incrementally. Proof-of-concept work is often used to validate assumptions early, reduce uncertainty, and create a roadmap with clear milestones and acceptance criteria.
What does the first 2–3 weeks of an Access modernisation typically look like?
We normally start with discovery and risk mapping: walkthroughs with users, an inventory of Access components (tables, queries, forms, reports, VBA/macros), and basic data profiling. Then we define a target approach and phased plan, including security baseline and migration strategy. Finally, we often run a small proof-of-concept on the riskiest workflow to confirm feasibility and refine the roadmap.
How do you modernise the user experience when users are used to Access screens?
We translate workflows rather than copy screens. A modern UX focuses on reducing steps, preventing errors, and making the “next action” obvious. We typically use prototypes to validate journeys early, and we design for accessibility and responsive use so the application works well on laptops, tablets, and mobiles where relevant.
How do you measure whether the modernisation has been successful?
Success is a mix of operational stability and business outcomes: fewer errors and corrections, faster task completion, better auditability, smoother reporting, and reduced dependency on a few key people. We also look for adoption signals during rollout, and we plan a controlled decommissioning of Access once the new system has proven itself in real use.