Replacing a homegrown MES: the people problem nobody plans for

Don't underestimate the complexity of replacing a homegrown MES/MOM.

When you've built something in-house, moving to a commercial platform brings challenges most manufacturers don't see coming. And the biggest ones usually aren't technical.

The developers who built it

Your in-house team can be your greatest asset or your biggest obstacle.

They know every quirk. The workarounds, the business rules, the integrations, the reasons things are the way they are. That knowledge is irreplaceable during a transition.

They're emotionally invested. They've spent years building something that worked. Watching it replaced can feel like a rejection of their efforts.

They can make or break the project. These are smart people. You want their energy going into making the new system succeed, not quietly undermining it.

The key is turning them from reluctant participants into champions:

• Give them ownership. Position them as the bridge between old and new. Make them super users. Give them a job title that reflects the new responsibility.
• Incentivise success. Financially or otherwise, tie their reward to the project landing well. Success can lift their careers significantly.
• Listen to them. They know where the old system's edge cases are buried. Use that knowledge in design and testing.
• Show them what's possible. Better analytics, AI, scalability, a modern experience for operators. Things they could never have built alone.

Treat them as partners rather than obstacles and they become your most powerful advocates. But don't let anyone sabotage the project from within. That's a leadership responsibility.

The "replicate everything" mentality

Because the homegrown system was built specifically for your operations, people expect the replacement to mirror every feature and quirk.

That creates unrealistic expectations. If leadership doesn't manage it, customisation creeps up and timelines stretch.

The 95% problem

The new system might handle 95% of requirements brilliantly. That missing 5% becomes the focus of all the criticism.

Strong voices fixate on what's different, rather than the big improvements: a better data model, better user experience, better reporting, AI capabilities and far more configurability. The advantages get lost in debates about recreating legacy behaviour.

Hidden complexity

Homegrown systems are full of undocumented workarounds, manual steps around the edges and tribal knowledge. They only surface during implementation, usually at the worst moment.

Spend time upfront mapping what the system really does, and what people do around it. Your developers are invaluable here.

Resistance to change

Users get attached to familiar workflows, even inefficient ones. Any change can feel like a step backwards rather than an opportunity.

That's normal. Plan for it. I cover how in Resistance to change is guaranteed.

The goal isn't to rebuild what you had

Your homegrown application is being replaced for a reason. It's time to move forward.

Replicating the old system inside the new platform isn't a path to success. It wastes the investment in modern capabilities and creates customisation you'll pay for at every upgrade.

Strong leadership keeps the project on track: minimise customisation, adopt industry best practice, and focus the team on the new system's strengths rather than recreating old limitations.

What's been your biggest surprise when replacing a homegrown system?