Reverse Engineering Legacy Systems: The Hidden Challenge No One Talks About

Legacy systems continue to support critical business operations long after the technology behind them becomes outdated. When organizations decide to modernize these systems, the biggest challenge is often not the new platform or tools, but understanding how the existing system actually works.

In this podcast episode, we examine the often-overlooked role of reverse engineering legacy systems and why it is essential for successful ERP, CRM, and web-based application modernization. This discussion is especially relevant for organizations running long-standing systems such as MS Access applications, custom desktop software, or legacy databases that have evolved over many years.

Podcast Overview

Reverse engineering legacy systems is not just a technical task, it is a business discovery process. Many legacy applications contain years of accumulated logic that reflects how a business truly operates today. Without extracting and documenting this knowledge, modernization efforts risk breaking core workflows, losing functionality, and disrupting daily operations.

In this episode, Doron Farber explains why reverse engineering should always precede system migration or ERP implementation and how it enables businesses to modernize with confidence rather than uncertainty.

Key Topics Covered in This Episode

• What reverse engineering means in legacy system modernization
• Why undocumented business logic is common in long-running systems
• How operational workflows become embedded in legacy applications
• The risks of modernizing systems without proper discovery
• Why reverse engineering is a foundational step for ERP and CRM transformation

Guest and Host

Guest Expert:
Doron Farber – Owner & Senior Developer, The Farber Consulting Group, Inc.

Host:
Sarah Greene

Podcast Conversation

Sarah Greene (Host):
Welcome back to DataTalk Live, where we explore the real challenges behind modern software and data systems. I’m your host, Sarah Greene, and today we’re tackling a topic that often gets overlooked until it causes serious problems:

Reverse Engineering Legacy Systems, the Hidden Challenge No One Talks About.

Joining me is Doron Farber, Owner and Senior Developer at The Farber Consulting Group, Inc. Doron has spent decades helping businesses modernize legacy systems without disrupting daily operations. Doron, great to have you here.

Doron Farber:
Thanks, Sarah. This is an important conversation because reverse engineering is one of the biggest factors that determines whether a modernization project succeeds or fails.

Sarah:
When businesses think about modernizing legacy systems, they usually focus on new technology or platforms. Why is reverse engineering such a critical step?

Doron:
Because legacy systems don’t just store data, they store decisions. Over time, business rules, exceptions, and workflows become embedded directly into the system. Many of those rules were never documented. Reverse engineering is about uncovering how the business actually operates today, not how it was originally designed years ago.

Sarah:
So even if a legacy system is still working, there can be hidden risks?

Doron:
Absolutely. A system can appear stable on the surface while hiding serious risks underneath. Employees adapt to limitations, work around problems, and pass knowledge informally. When those people leave or when the system needs to change, that undocumented logic becomes a major liability.

Sarah:
Why do so many legacy systems end up undocumented in the first place?

Doron:
Most legacy systems evolve organically. Features get added to solve immediate needs, often under time pressure. Over years or decades, documentation falls behind reality. Eventually, the application itself becomes the only record of how the business works.

Sarah:
What typically happens when companies skip reverse engineering and jump straight into rebuilding or migrating a system?

Doron:
They run into surprises, missing reports, broken workflows, unhappy users. Critical functionality gets lost because no one realized how much logic was tied to the old system. That leads to delays, cost overruns, and sometimes a loss of trust in the new system.

Sarah:
Some businesses worry that reverse engineering will slow down their modernization efforts. Is that a valid concern?

Doron:
It’s actually the opposite. Skipping reverse engineering might feel faster at the start, but it almost always slows projects down later. Reverse engineering reduces risk. It allows teams to make informed decisions and prevents costly rework once the new system is already in place.

Sarah:
From a business perspective, what does reverse engineering protect?

Doron:
It protects continuity. Businesses rely on their systems every day to process orders, manage inventory, generate reports, and make decisions. Reverse engineering ensures that modernization improves those processes instead of disrupting them.

Sarah:
In your experience, what’s the biggest misconception businesses have about legacy systems?

Doron:
That old systems are simple or outdated just because they’re old. In reality, many legacy systems are complex because they’ve been shaped by years of real business needs. That complexity has to be understood before it can be modernized successfully.

Sarah:
What advice would you give to decision-makers who are considering modernizing a legacy system?

Doron:
Start by understanding what you already have. Before choosing new software or starting development, invest time in reverse engineering. Identify workflows, business rules, and dependencies. That knowledge is what turns modernization into a strategic improvement instead of a risky experiment.

Sarah:
That’s a powerful takeaway. Doron, thank you for sharing your insights.

Doron:
Thanks, Sarah. It’s always great to talk about topics that can help businesses avoid costly mistakes.

Sarah:
And to our listeners, if your organization depends on a legacy system and modernization is on the horizon, remember that understanding your current system is the first step to doing it right. Thanks for tuning in to DataTalk Live. Until next time.