Short answer
A SaaS migration is planned as data field mapping, a trial migration, reconciliation checks, a scheduled cut-over and post-migration monitoring. Loading the transfer file is not the completion criterion; record counts, relationships and critical workflows must be verified in the new system.
Discovery and mapping
Inventory source tables, files, users and relationships. Define field mapping, transformations and missing-record rules. Assign ownership to each data area.
Rehearsal and reconciliation
After a sample migration, check counts, relationship integrity and business totals. Error reports should identify which records failed and why.
Cut-over
Schedule final changes, write freezes, user transition and rollback. Prevent uncontrolled updates to old and new systems at the same time.
After migration
Retest permissions, critical workflows and integrations. Monitor exceptions and reconciliation closely during the transition. Agree on archiving before retiring access to the old system.
Rollback plan
Before cut-over, write down up to which point a rollback is possible and who decides. If the old system will keep accepting changes, it must be clear how those changes will reach the new system, or how writing will be stopped at cut-over.
A practical evaluation exercise
Try field mapping on a small data group first. Compare record counts, relationships, attachments and dates between source and destination. Decide whether the old system accepts changes after cut-over. Name the acceptance owner and last viable rollback time; uploading a file alone does not establish a successful migration.
Frequently asked questions
Two questions we are often asked on this topic.
Do we need to shut the system down during migration?
Not always, but uncontrolled writing to both the old and the new system must be prevented at cut-over. A short write freeze is often the safest route.
When should I close access to the old system?
After data reconciliation is complete, archive needs are determined and the responsible teams have approved. Closing too early creates a risk of lost evidence and data if a problem is found later.
