The real fear when switching HR systems isn't learning a new interface. It's losing something along the way: the record of who used which laptop, the reason someone took an unpaid leave two years ago, or the trail behind a vacation balance adjustment nobody quite remembers but someone will eventually need to explain. A badly planned migration doesn't delete data outright — it orphans it, strips away context, until it's useless.
The good news is that most of that risk disappears with a plan: deciding what gets migrated first, what becomes a fresh record with a note pointing to its history, and what simply isn't worth dragging along.
What to migrate first: master data
Before anything else, load the basic structure: employees, departments, and job positions. That's why a master-data import template (an Excel spreadsheet you fill in once) matters so much at the start — it lets you onboard your entire headcount at once, department and position already assigned, instead of creating each record by hand. Without this foundation loaded correctly, everything that comes after — leave, equipment, performance reviews — has nowhere to attach to.
IT equipment: decommission it, don't delete it
A common mistake during migration is treating the equipment inventory as a list you can simply tidy up. But a laptop with history — who had it before, when it was last serviced — shouldn't be removable without a trace. The right approach, both in the new system and during any migration, is to decommission a unit while keeping its serial number and history intact, rather than deleting it as if it never existed. If your old system lets you delete equipment outright, that's exactly the data worth rescuing before you switch it off.
Leave history: what's actually worth carrying over
Not all history deserves the same level of detail in the new system. Current vacation balances and leave types are critical from day one — someone will request time off in the first week. The line-by-line detail of every absence from three years ago, on the other hand, can live as a summary or a separate archive: what matters is that the opening balance is correct, not reconstructing every row of history nobody is going to audit.
Permissions: don't migrate the chaos, redesign it
Migrating isn't just about moving data — it's also the moment to fix what was never configured properly. If the old system relied on generic admin/editor/viewer roles that forced you to over-grant access just to solve one specific case, there's no reason to copy that same structure into the new system. Use the migration as the moment to define granular permissions per module, with their own level (read, write, admin) and scope (own, team, company-wide) — it's more work on day one, but it stops the same problem from dragging on for another five years.
The practical rule: migrate first whatever other data depends on to exist (people, departments, positions), protect what can't be rebuilt if lost (serial-numbered equipment, the reasons behind balance adjustments), and summarize the rest. A new system that starts with clean, traceable data is worth more than one dragging ten years of poorly attached detail.