5 HCM Data Migration Myths (and What Actually Goes Wrong)

HCM migrations fail in predictable ways — usually because of an assumption made at the start. Here are five myths that cost projects time and credibility, and what actually goes wrong.

Myth 1: “The HR vendor’s tool will handle the data”

Target-system tooling loads data; it doesn’t extract from your legacy system, map decades of custom fields, or reconcile the result. The gap between “export” and “clean, mapped, reconciled load” is the whole project.

Myth 2: “We only need current employees”

Terminated employees, retirees and historical payroll are exactly what you’ll be asked for during a tax notice, audit or dispute. Scope history in from day one — or archive it deliberately, not by accident.

Myth 3: “It’s just a data dump”

Effective-dated records, assignments, and the difference between a person and their employment relationship all have to be modelled correctly in Fusion. A flat dump doesn’t reconstruct that.

Myth 4: “Payroll will reconcile itself”

Payroll is where errors are most visible and least forgivable. Balances, deductions and tax data need explicit reconciliation, ideally a parallel run, before anyone trusts the first live pay cycle.

Myth 5: “We’ll clean the data later”

Data-quality issues surface as load failures — value-set mismatches, over-length fields, non-numeric values in numeric columns. Catching them in staging (load-readiness checks) is far cheaper than discovering them mid-import.