How to Switch HR Software Without Disrupting Your Business

Switching HR software is one of those tasks that seems straightforward until you start. The employee data is not all in one format. The payroll history is in the old system. The documents are in shared folders. The migration takes longer than expected. The practical advice is to plan the migration before you give notice on the old system — not after.

The key data sets to migrate are: employee master records (name, address, contact, bank details, start date, job title, salary, contract type), current leave balances, year-to-date payroll figures (if switching mid-year), current documents (contracts, warnings, certifications), and outstanding absence records. Most HR platforms export employee data as CSV. Mellow imports from CSV directly — the import template is available before you commit to switching.

The practical migration sequence is: export from old system; clean the data (resolve duplicates, fill missing fields); import to Mellow in a test run; validate the record count and key fields against the export; go live with the next payroll run. Mid-year payroll migrations require particular care: year-to-date tax and NI figures must be imported correctly so that the annual P60 calculations are accurate. Mellow's onboarding team walks through this with new customers. The migration is manageable — the plan just needs to be made before it becomes urgent.