What causes an Unreal DataTable row struct mismatch?

The CSV header names or types do not match the UStruct's UPROPERTY fields, so Unreal cannot map columns to members and silently leaves rows empty or rejects the import.

How do I catch this when it only happens for some players?

Capture it automatically from the player's device with the full stack trace, the device and OS, the build, and a breadcrumb trail of what they did. That turns a vague complaint into a specific, reproducible issue you can fix without owning the hardware it happens on.

How to Fix an Unreal DataTable Row Struct Mismatch on Import

Quick answer: Make the CSV column headers exactly match the struct property names, ensure the struct derives from FTableRowBase, and check the import log for unmapped columns.

Your DataTable imports but every row is zeroed, or the import is refused. Unreal maps CSV columns to struct fields by name. If the header is Damage but the field is BaseDamage, the column is dropped.

How to fix it

1. Match header names to fields

Each CSV column header must equal the UPROPERTY name exactly (case-sensitive), and the first column must be Name for the row key.

2. Derive the struct correctly

Your row struct must inherit from FTableRowBase and mark every importable member with UPROPERTY(BlueprintReadOnly) so the importer can see it.

3. Read the import log

Open Output Log during import; Unreal lists columns it could not map and rows it skipped, which points directly at the mismatched header or unsupported type.

Catching the ones you can't reproduce

The hardest version of this to fix is the one you can't reproduce — it only happens on a player's hardware, OS, driver, or save state, under conditions that simply aren't present on your machine. A report that says “it crashed” or “it froze” gives you nothing to act on, so the bug survives release after release while quietly costing you players.

Automatic error capture closes that gap. Each failure arrives with its full stack trace, the device and OS, the build number, and a breadcrumb trail of what the player did right before it broke, so even a failure you have never seen becomes a specific, reproducible issue. Fold identical failures into one signature ranked by how many players each hits, and your worklist sorts itself worst-first instead of arriving as a stream of vague complaints.

This is where a tool like Bugnet earns its place. Its SDK captures every Unreal Engine error automatically with the full stack trace plus device, OS, memory, build, and game-state context, folds duplicates into one grouped issue with an occurrence count, and ties each to the build it first appeared on — so you fix the problem that hurts the most players first and confirm it is gone when its signature disappears from the next release.

The bug you can't reproduce isn't gone — it's just invisible until you capture it from the player's device.