To switch ecommerce analytics platforms successfully, audit and export your existing data before disconnecting anything, define the KPIs and formulas your new platform must match, run both platforms in parallel for at least 2-4 weeks to validate that the new system's numbers agree with the old one on known metrics, then cut over fully once the validation is complete. Most ecommerce analytics migrations fail not during setup but during validation, when teams discover the new platform calculates a key metric differently and spend weeks trying to reconcile numbers instead of using them.