Fixing Common Upload Failures
Diagnose and fix the most common reasons CSV uploads fail, including encoding issues, missing columns, and file size limits.
FILE_TOO_LARGE Error
If you see a 'File too large' error, your file exceeds the size limit for your plan. Free and Starter plans accept files up to 10 MB. Pro accepts up to 50 MB. Agency accepts up to 200 MB. The most common cause is exporting a CSV from a database with unnecessary columns included.
To fix this, re-export your CSV with only the columns that are needed for enrichment (email, first_name, last_name, phone, company are sufficient). Removing unused columns typically reduces file size by 50–80% for wide database exports.
Tip
Use a spreadsheet tool to delete unused columns before export. In Excel: select unused columns → right-click → Delete. In Google Sheets: select unused columns → right-click → Delete columns.
NO_EMAIL_COLUMN Error
The NO_EMAIL_COLUMN error means Trust Leads could not detect a column containing email addresses. This usually happens when the email column has an unusual name that the auto-detection engine does not recognise, or when the email addresses are stored in a column alongside other data.
Solution: rename your email column to 'email' before uploading, or use the column mapping screen to manually assign the correct column to the email field. The column mapping screen appears after upload and allows you to override any auto-detected mapping.
ENCODING_ERROR
CSV files encoded in formats other than UTF-8 (such as Windows-1252, Latin-1, or ISO-8859-1) can cause character encoding errors, especially when the contact data contains non-ASCII characters (accented letters, Asian characters, special symbols).
To fix encoding issues: in Excel, use 'Save As' and select 'CSV UTF-8 (Comma delimited)' from the format dropdown. In Google Sheets, export as 'Comma-separated values (.csv)' — Sheets always exports in UTF-8. In Python/pandas: df.to_csv('output.csv', encoding='utf-8-sig') adds a BOM that Excel-exported files often need.
# Fix encoding in Python before upload
import pandas as pd
df = pd.read_csv('leads.csv', encoding='latin-1') # read in original encoding
df.to_csv('leads_utf8.csv', encoding='utf-8', index=False) # save as UTF-8INVALID_CSV_FORMAT Error
This error means the file is not a valid CSV. Common causes are: saving an Excel .xlsx file with a .csv extension without actually converting it; CSV files with inconsistent quoting or escaping; or files that use a tab or semicolon delimiter instead of a comma.
Fix by opening the file in a text editor and inspecting the first few lines. You should see comma-separated values with a header row. If the file uses semicolons (common in European Excel exports), open it in Excel, use Data → Text to Columns with semicolon as delimiter, and re-export as CSV.
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