Asking for file help when the original cannot be shared

Build a small fictional file with the same format, columns, and troublesome pattern. Share its type, approximate size of the real file, the steps you took, and the expected versus actual result.

Do not upload the private original, hidden metadata, or screenshots containing names or tokens. If the failure occurs only with real data, simplify carefully until a safe sample still reproduces it. State which details were changed so helpers do not infer the wrong cause.

What pattern must the sample preserve?