How to Migrate Off NetSuite (Or Any ERP) Without Breaking Operations

Most ERP migrations go poorly. Industry surveys consistently put major-scope migration failure rates at 30–50%. The companies that succeed share a pattern that's almost the opposite of what most migrations actually do.

Here's the playbook for migrating off NetSuite (or any ERP) — to a custom replacement, to a different ERP, or to a phased combination — without breaking operations.

Why most migrations fail

Three recurring patterns:

Big-bang cutover. Turn off the old system, turn on the new system, same day. Discover the dozens of edge cases that weren't migrated cleanly. Operations stop. Customers complain. Pressure forces rollback or improvisation.

Insufficient data cleanup. The new system inherits the old system's mess plus migration errors. Dirty data compounds.

No parallel run. Without running both systems side-by-side, you can't validate the new system handles real operations correctly until it's the only option.

The playbook that works

Phase 1: Discovery and audit (weeks 1–4)

Document what NetSuite is actually doing for you today. Not what it could do — what it does. Most companies use 30–50% of their ERP's features; the migration scope should cover those, plus any features you want that aren't currently working well.

Output: a "current state" document that captures every workflow, integration, custom field, custom report, and edge case the new system needs to handle.

Phase 2: Build or configure the new system (weeks 5–20)

If building custom, this is where the weekly-demo cadence matters most. You're translating an enterprise system; the smallest missed detail can cause real operational disruption.

If migrating to another ERP, this is configuration and customisation work.

Either way: include data migration scripts as part of the work. Don't leave migration for the end.

Phase 3: Parallel run (weeks 21–26)

Both systems run live. Daily transactions enter both. Reconciliation reports run daily. Discrepancies get investigated and resolved before they compound.

This phase is non-negotiable. It's where you discover the 5–10% of edge cases that weren't caught in discovery. Skipping it is the #1 cause of migration failure.

Phase 4: Cutover (weeks 27–28)

Pick a low-volume window (post-month-end is ideal for ERP). Cut over operations to the new system. Keep the old system in read-only mode for 90 days for reference.

Phase 5: Stabilization (weeks 29–36)

The first 60–90 days post-cutover surface edge cases. Budget engineering capacity to handle them. Don't try to add new features yet — stabilise first.

Data migration: the part that breaks

Data migration is where most migrations go off the rails. Three rules:

Migrate clean data, not raw data. Cleanup before migration, not after. Once data lands in the new system, cleaning it is 5x harder.

Migrate in stages. First reference data (customers, vendors, products, accounts). Then current transactions. Then historical transactions. Each stage validated before the next starts.

Reconcile religiously. For every migration batch, prove the new system has the right totals. If $X went into the migration, $X needs to come out, with the same counts per category.

What this costs

For a typical mid-market NetSuite migration:

Discovery and audit: $15–30k, 4 weeks

Custom system build (if going custom): $90–220k, 14–22 weeks — see our ERP cost breakdown

Data migration scripts: $15–40k, 3–6 weeks

Parallel run engineering capacity: $10–20k, 6 weeks

Stabilization period: budgeted maintenance retainer

Total typical: $130–310k over 6–9 months for a Tier 2 mid-market migration.

When to migrate

Right times:

Post month-end, quarter-end, or year-end (depends on your fiscal calendar)

Low-volume season

When you have engineering capacity to handle unforeseen issues

Wrong times:

Mid-quarter

Black Friday or December for retail

Tax season for financial services

Mid-acquisition or other organisational change

When NOT to migrate

If your NetSuite is working and the only complaint is cost, do the cost-benefit carefully. NetSuite at $80k/year vs custom at $200k upfront + $40k/year — breakeven is around year 2–3. If you're 5 years in and growing, custom usually wins. If you're 1 year in and growing fast, stay put another year.

For a transparent cost estimate for your specific migration scope, our cost calculator runs 5 questions. Or contact us to discuss your migration timeline and cost.