10 Real-Life ERP Lessons Theory Won’t Tell You

Alex at FitGap

08 Nov 2025 — 3 min read

You can master every methodology and memorize every phase gate—then real life shows up. ERP implementations (including D365 Finance) don’t fail because people forgot the theory; they wobble because reality keeps moving. These are field notes you only learn by shipping.

1) The business will be called upon far more than expected

Key users don’t just “attend workshops.” They design, validate, reconcile, approve, and put out fires—while doing their day jobs. If you don’t protect their time, fatigue hits early and quality drops.

What to do: lock capacity for business validation up front (by role and sprint), plan backfills during UAT/cutover, and publish a simple RACI so no one is “voluntold” last minute.
Related post: https://www.fitgapfinance.com/roles-responsibilities-in-an-erp-implementation-project/

2) Requirements keep emerging as the system gets real

Workshops feel exhaustive—then users touch the system and see gaps. That’s normal. Discovery continues when reality meets screens.

What to do: expect a controlled inflow. Maintain a visible backlog, score changes by value/risk, and tie every change to scope, timeline, and data impact before you say yes.
Related governance post: https://www.fitgapfinance.com/erp-governance-roles-escalation-culture-d365/

3) Early phases over-analyze; later phases force focus

Month 1: everything is “critical.”
Month 7: only what’s truly essential survives.
Pressure clarifies priorities.

What to do: define the non-negotiable MVP early (ledger, tax, core invoicing, inventory, key controls) and protect it. Park “nice-to-have” items without guilt.

4) Resistance is inevitable—manage the emotion, not just the process

People don’t resist change; they resist losing control or expertise. Slide decks won’t fix that.

What to do: involve respected business leads early as ambassadors, narrate “what stays the same / what changes / why it’s safer,” and show quick wins that matter to front-line users.
More on this: https://www.fitgapfinance.com/human-side-erp-projects/

5) De-scoping will happen—and it’s not failure

Theory loves completeness; reality rewards focus. Keeping everything guarantees nothing ships well.

What to do: run formal scope reviews at each phase gate. If something threatens the MVP, move it post-go-live with a clear owner and date. Celebrate de-scoping that de-risks cutover.

6) Change requests will be frequent—process or chaos, pick one

Without change control, every meeting becomes a negotiation. You won’t stop change; you can only channel it.

What to do: enforce a simple, visible CR process:
business case → impact (process, data, integrations, security, testing) → governance sign-off.
No CR, no work.
Governance guidance: https://www.fitgapfinance.com/erp-governance-roles-escalation-culture-d365/

7) Misalignment starts with fuzzy objectives

When goals aren’t explicit, everyone fills in the blanks differently—IT, Finance, Operations, and vendors drift in parallel.

What to do: publish a one-page “North Star”: objectives, out-of-scope, MVP definition, quality bar, and decision rights. Revisit it in every steering committee.
Related post: https://www.fitgapfinance.com/roles-responsibilities-in-an-erp-implementation-project/

8) Security and reporting won’t be perfect at go-live

You can test forever and still miss real-world combinations of roles and reporting needs. The first 4–8 weeks reveal what matters most.

What to do: plan a stabilization lane with capacity for role tweaks, row-level security, and “first wave” reports. Track requests, batch deployments, and communicate weekly.
Security guidance: https://www.fitgapfinance.com/erp-security-roles-d365-finance-governance-approach/

9) Documentation always lags change

As-designed docs age quickly once users start working differently. Over-documenting creates a museum—nice, but not helpful.

What to do: document the essentials (key flows, controls, roles, integrations) and assign explicit ownership. Treat living docs like product, not artifacts.

10) Success is 80% alignment, 20% configuration

The best setup won’t save you if governance is weak and stakeholders aren’t synced. Relationships and expectations move the needle more than parameters.

What to do: keep IT, Finance, and Operations in rhythm: shared backlog, transparent risks, and ruthless decision hygiene (one owner, one date, one outcome).
Environment context: https://www.fitgapfinance.com/erp-implementation-environment-strategy/

Field-Proven Checkpoints

Capacity: business time reserved for UAT, reconciliation, and cutover (on calendars, not wish lists).
MVP: a written, signed list of go-live must-haves—reviewed each phase.
CR process: intake form, impact grid, approval path, weekly cadence.
Stabilization plan: roles/reporting backlog with a dedicated post-go-live squad.
North Star: single page with objectives, scope boundaries, and decision rights.