Excel contact files break because spreadsheets don’t store contact logic, only values. Phone numbers lose country codes, names split incorrectly, and leading zeros vanish because Excel auto-formats cells. Contact apps expect structured data, not raw tables. That gap causes formatting loss during import. This is why many users convert spreadsheets before transferring contacts. A desktop solution like Softaken Excel to VCF Converter translates Excel data into proper contact attributes instead of guessing. It preserves number formats and labels so mobile apps read the data correctly instead of rewriting it.