Migrating from Dynamics NAV to Business Central: What Changes, What Breaks, and How to Do It Right

If you’re running Dynamics NAV — whether NAV 2009, 2013, 2015, 2017, or 2018 — you already know the migration conversation is looming. But between the competing upgrade paths, the uncertainty about what happens to your customizations, and the pricing that nobody publishes, it’s hard to know what’s real and what’s partner marketing.

This article cuts through that. Here’s exactly what changes when you move from NAV to Business Central, what will break, what you’ll gain, and what it actually costs — from a partner who’s done it for companies on every NAV version from 2009 forward.

Why Migrate Now?

Let’s state the obvious: nobody wakes up excited about an ERP migration. But the clock isn’t on your side.

NAV 2018 mainstream support ended January 2023. Extended support runs to January 2028 — but “extended support” means Microsoft will fix something if it breaks catastrophically. It doesn’t mean security patches, regulatory updates, or new features. For NAV 2017 and older, you’re already on borrowed time — or fully end-of-life.

Beyond support deadlines, there’s the security reality. An unsupported on-premise ERP with a SQL Server backend, exposed to a network, running code that hasn’t been patched in years — that’s not a hypothetical risk. Your IT team knows it. Your auditors will start asking about it. And every month you wait, the gap between your ERP and the modern Microsoft ecosystem gets wider.

The question isn’t whether to migrate. It’s which path to take, and how to do it without the horror stories.

Already familiar with what Business Central is and how it differs from NAV at a high level? Read our Business Central vs Dynamics NAV comparison first, then come back here for the migration specifics.

The Three Migration Paths

Not all NAV-to-BC migrations are equal. The path you take depends on your NAV version, your customization footprint, and how much you’re willing to rethink.

Path 1: Technical Upgrade (Data Only, Rebuild Customizations)

What it is: Your NAV data gets migrated to Business Central, but your customizations don’t. Every C/AL modification — reports, pages, codeunits, table extensions — gets triaged and rebuilt as AL extensions. Your business processes stay largely the same; the only thing that changes is the platform underneath them.

Best for: NAV 2016–2018 with moderate customizations where the business logic is still valid. Companies that like their processes but want a modern platform.

Reality check: This is the most common path, and it’s what most people mean when they say “NAV upgrade.” The data migration is straightforward because BC shares NAV’s DNA. The customization work is the variable — more C/AL = more AL rewrite effort.

Path 2: Full Reimplementation (Start Fresh)

What it is: You don’t migrate anything except master data and open transactions. You start with a clean Business Central environment, configure it to match your current processes (or improve them), and treat the project like a new Business Central implementation. No customization rewrite — you design what you need from scratch.

Best for: NAV 2009–2015 where customizations are extensive and often obsolete. Companies that want to fundamentally rethink their processes rather than replicate them. Multi-entity businesses where intercompany logic needs a redesign.

Reality check: This takes longer (3–5 months minimum) but produces a cleaner result. You’re not paying developers to translate 2009-era C/AL code that was written by a partner who’s no longer in business. You’re building what you actually need now.

Path 3: Hybrid (Phased Migration)

What it is: You migrate your data and your most critical customizations in phase 1 — go live with finance and core operations. Phase 2 brings the remaining customizations, integrations, and advanced modules. It’s a structured rollout, not a big-bang cutover.

Best for: Companies that can’t afford a single extended go-live window. Businesses where some modules (manufacturing, service management) are mission-critical and some are “nice to have.” Companies with complex integrations that need staged rebuilding.

Reality check: This is the lowest-risk path and what we recommend for most mid-size companies. You get value faster (finance goes live in 8–10 weeks), your team absorbs change in manageable chunks, and if something goes wrong in phase 1, it doesn’t take the whole business down with it.

Real customer paths we’ve delivered:

What Fundamentally Changed: NAV vs Business Central

Understanding what changed is the difference between a well-scoped migration and an expensive surprise. Here’s the honest breakdown.

The “What Breaks” Honesty Section

Every migration has casualties. Here’s what you should expect to lose — and what you can do about it.

1. C/AL Customizations (Every Single One)

There is no migration path for C/AL code. None. Every custom report, modified page, extended table, and custom codeunit must be reimplemented in AL or retired.

The silver lining: Most NAV instances have 30–50% dead code. Reports nobody runs. Features built for employees who left. “Temporary” workarounds from 2016 that became permanent. A migration is the best cleanup opportunity you’ll ever get. We typically retire 30–50% of C/AL modifications because standard Business Central now covers that functionality.

For what remains: the business logic is preserved. It’s the same rules, same calculations, same validations — just in AL instead of C/AL, and sitting cleanly on top of the base application where future Microsoft updates won’t touch it.

2. ISV Add-ons Without BC Versions

Most major ISV solutions — Jet Reports, Continia, LS Retail — have Business Central versions and migration paths. But smaller, niche, or older add-ons often don’t. If your document capture tool was built by a local partner in 2012, it’s probably not getting a BC port.

What to do: During the assessment phase, inventory every ISV solution. Check AppSource for BC equivalents. For anything without a path forward, either find an AppSource replacement or build the functionality as a custom AL extension.

3. File-Based Integrations

If your NAV talks to other systems by dropping CSV files into shared folders or reading XML from FTP servers — those integrations will break. Business Central’s SaaS model doesn’t give you filesystem access on the server.

What to do: Replace file-based integrations with REST APIs (BC has extensive built-in API endpoints) or Power Automate flows. Most of the time, the replacement is better — real-time sync instead of batch, proper error handling, audit trails. But it’s work that needs to be scoped.

4. COM and Automation Objects

NAV automation — controlling Excel, Word, or Outlook through COM interop — doesn’t exist in Business Central SaaS. There’s no Windows COM layer to call.

What to do: Nearly every COM automation use case has a better BC-native alternative. Excel reports become Power BI or BC’s built-in Excel integration. Outlook automation becomes the BC Outlook add-in or Power Automate. Document generation becomes Word layouts. It’s more work up front, but you’re replacing fragile hacks with supported features.

5. Old NAV Reports (Classic, Pre-RDLC)

NAV 2009 and earlier used the Classic report writer. These reports have no migration path to Business Central whatsoever. They need to be completely rebuilt.

What to do: Rebuild as Word layouts (for printable documents like invoices and statements), Excel layouts (for analytical reports), Power BI dashboards (for interactive reporting), or AL-based custom reports. In our experience, the rebuilt reports are universally better — interactive, filterable, and automatically refreshing.

What actually survives:

• Your data — all of it, if you want it
• Your chart of accounts and dimensions
• Your posting groups and posting logic
• Your business processes (the logic transfers, even if the code doesn’t)
• Your user permissions structure (translated, not copied)

What You Gain

It’s not all breaking and rebuilding. Here’s what you get on the other side that you don’t have today.

Modern Web & Mobile Interface

The browser-based UI works identically on desktop, tablet, and phone. No Remote Desktop, no VPN, no Citrix. Your warehouse team can check inventory from a tablet. Your sales team can create quotes from their phone. Your finance team can approve purchase invoices from home.

Power BI Integration

Real-time dashboards that pull directly from Business Central data. No exports, no manual refresh, no “the report is from last week.” Sales performance, cash flow, inventory turns, customer profitability — all live.

Built-in AI and Copilot

Copilot is built into Business Central — not bolted on, not a separate SKU. AI-generated product descriptions. Bank reconciliation suggestions. Late payment prediction. Analysis tabs that answer “why did margin drop this quarter?” without a report. More capabilities ship every month.

Automatic Updates

Monthly updates with zero downtime (SaaS). Two major release waves per year. You’re never behind on features, security, or regulatory compliance. Compare that to your current NAV: when was the last time it got an update?

AppSource Marketplace

Thousands of ready-made extensions — approval workflows, document capture, shipping integrations, EDI, advanced financial reporting, industry-specific solutions. Install in minutes from a marketplace, not months from a development project.

Teams Integration

Business Central data inside Microsoft Teams. Share records in chat. Get adaptive card notifications when something needs attention. Approve purchase orders without opening BC. Your ERP becomes part of how your team already communicates.

Modern APIs

REST APIs with proper documentation, OAuth authentication, and Power Automate connectors. Integrations that used to take weeks of custom web service development can now be built in hours — and maintained without touching the ERP code.

Timeline by NAV Version

How long your migration takes depends heavily on which NAV version you’re on and how customized it is. Here’s what we see in practice.

The NAV 2018 advantage: If you’re on NAV 2018 and your partner already moved your customizations to the extension model, you’re in the best position. The migration is predominantly data and configuration — minimal code rewrite. This is the 2-month path. If you’re on NAV 2018 but still running C/AL modifications, add 1–2 months for AL rewrite.

The NAV 2009 reality: You’re not doing a technical upgrade. You’re doing a reimplementation that happens to share a data model with your target system. The good news: Business Central’s standard features now cover functionality that required heavy customization in 2009 — manufacturing, warehousing, intercompany, multi-currency. What took 40 C/AL objects in 2009 might be 5 AL extensions today.

Pricing Guidance

Nobody publishes real migration pricing. Here it is.

Migrating from NAV to Business Central typically costs 50–70% of what a new BC implementation would cost for the same scope. The discount comes from familiar data structures (less mapping effort), known processes (less discovery), and users who already understand the ERP paradigm (less training).

Microsoft licensing is on top. A 20-person company migrating from NAV to BC SaaS typically pays €450–650/month in licensing — often less than what they were paying in NAV enhancement plans. BC’s tiered model (Team Member at $8/month, Essentials at $70/month, Premium at $100/month) means you license people for what they actually do, not for having a login.

What makes it more expensive:

• Heavy C/AL customization footprint (more rewrite effort)
• Dirty master data requiring extensive cleansing
• Complex integrations needing full rebuilds
• Multi-entity setups (intercompany, consolidation, multi-currency)
• Delayed decisions that extend the project calendar

What keeps costs down:

• Clean data — invest time in cleanup before the migration starts
• Decisive project lead who can make calls without escalation
• Willingness to retire unused customizations instead of rewriting them
• Phased approach — finance first, operations later
• Using AppSource extensions instead of building everything custom

For a full breakdown of BC implementation costs — including licensing, hidden costs, and what drives the price — see our Business Central implementation costs guide.

Migration Prep Checklist

Before you talk to a partner, here’s what to have ready. The more of this you can answer, the faster you’ll get an accurate timeline and price.

Know Your Current Setup

• NAV version and build number (find it in Help → About)
• Database size (in GB) and approximate row counts for key tables
• List of all C/AL modifications (modified objects, new objects, custom reports)
• List of all ISV solutions and their versions (Jet Reports, Continia, LS Retail, etc.)
• Number of users by role (finance, sales, purchasing, warehouse, shop floor, read-only)

Know Your Data

• Number of active customers and vendors (not the total count — the active ones)
• Number of inventory items and whether descriptions are standardized
• Approximate volume of posted entries (G/L entries, customer ledger entries, vendor ledger entries)
• Any known data quality issues (duplicate customers, orphaned records, unreconciled balances)
• How much history you want to bring to BC (2 years? 5 years? everything?)

Know Your Integrations

• Every system that connects to NAV (e-commerce, payroll, CRM, warehouse, banking, reporting tools)
• How each integration works (API, file drop, database link, manual export/import)
• Which integrations are critical vs. nice-to-have

Know Your Decision-Makers

• Who is the project sponsor? (Executive with authority to remove roadblocks)
• Who is the project lead? (Person with 8–12 hours/week to dedicate)
• Who makes financial structure decisions? (CoA, dimensions, posting groups — hard to change later)
• Who signs off on go-live readiness?

Know Your Timeline

• Preferred go-live window (avoid year-end close, busy season, audit periods)
• Any hard deadlines (extended support expiration, lease renewal on server hardware, audit findings)

The Bottom Line

Migrating from Dynamics NAV to Business Central is not a small project. Your customizations need rewriting, your integrations need rebuilding, and your team needs retraining on a browser-based interface. There’s no magic “upgrade button.”

But it’s also the most predictable ERP migration path in the Microsoft ecosystem. The data structures are familiar. The business logic carries forward. The operational disruption, compared to switching ERP platforms entirely, is minimal.

And on the other side, you get a platform that updates itself every month, integrates natively with the tools your team already uses, and gets better with every release — rather than one that’s frozen in time, drifting further from support and security with each passing quarter.

If you want an honest assessment of what a migration would look like for your specific NAV version and setup, book a free discovery call. No pitch, no pressure — just 30 minutes with someone who’s done this before.

→ Explore our Business Central implementation services

Vanguard 360 Solutions is a Microsoft Dynamics 365 Business Central partner and LS Retail Gold Partner. We’ve completed over 50 end-to-end implementations across Europe, the UK, UAE, and Saudi Arabia, including migrations from every NAV version from 2009 through 2018.