A runtime error when importing leads could be due to issues with your CSV file, like having too many columns (over 72), too many rows (over 50,000), or including columns like "created at" or "updated at." Make sure your file is UTF-8 encoded and uses commas as separators. If you’re still stuck, click into the error cell for more details, and try using Sculptor in the top-right corner to help troubleshoot. Let me know if Sculptor helps or if you want to share the error details here for more help!