Unreal Engine 5: Build failed with error : “Ensure Condition Failed: Build Faces(Pool, InVertices, ConflictV, HorizonEdges, FacesToDelete, NewFaces)

✍ Last Updated : December 1, 2022

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![Untitled](Unreal Engine 5 Build failed with error %E2%80%9CEnsure Co 864e570a660d41c292a2da84cad673aa/Untitled.png)

The problem only happens when packaging project. Most likely due to inconsistent collision normal inside the included maps.

The most case happens on spline generated static mesh. The usual hint about the error is where there is no collision on a specific part of the spline even if the spline static mesh source has.

![Example of the spline collider problem which is causing build failed. The part highlighted in red has no collision even if the source static mesh has](Unreal Engine 5 Build failed with error %E2%80%9CEnsure Co 864e570a660d41c292a2da84cad673aa/Untitled 1.png)

Example of the spline collider problem which is causing build failed. The part highlighted in red has no collision even if the source static mesh has

There’s no exact solution to solve the problem except to find the offending colliders and fix it.