Quick answer: Unreal Data Table import from CSV silently dropping rows? The first column is the row name and duplicates overwrite earlier rows — you lose data without warning.

An items.csv with 200 entries imports as 150 rows because some item IDs repeat (variant skins sharing an ID).

First Column = Row Name

By DataTable convention, the first CSV column is the row name. Two rows with the same name — the second overwrites the first. No error, no warning by default.

Validate Pre-Import

Lint your CSV with a small script: ensure column 1 is unique. Catches the bug before import.

Choose Row Names Carefully

Compose row names if no unique field exists: SwordBronze_Variant1. Use deterministic naming so manual edits stay consistent.

Compound Keys

If you have a (Item, Variant) pair, concat them into one row name. The data table stays unique; gameplay code reconstructs the parts on lookup.

Verifying

Row count after import matches your CSV row count. No silent merges. Lookup by row name returns the expected entry.

“DataTable column 1 must be unique. Validate before import to catch silent overwrites.”

Add a CSV-validation step in CI — cheap script, prevents very confusing data drift bugs in production.