Copy first. Verify. Only then clean up.
- Inventory files, shared folders, permissions, metadata, and retention settings.
- Export or copy to the new provider without deleting the old source.
- Check file counts, dates, original quality, shared access, and a sample restore.
- Update devices and collaborators, then keep the old account until your retention window is complete.
Warning: sync tools can propagate deletion. Maintain an independent backup during the move.