In most cases, reputable paid converters are built to handle enterprise-sized contact lists. Unlike lightweight free scripts or browser sites, premium desktop tools manage memory more efficiently and validate data as they go. Look for software that explicitly mentions bulk Excel contact support, error logging, and crash prevention mechanisms. A stable converter will also allow you to preview and validate before creating a VCF file to avoid silent losses. For example, Softaken Excel to VCF Converter is designed to handle large XLSX and XLS files in one go, providing consistent results without loss of contact fields or corrupted entries.