MRC file validation failing with some files

[holsam]

Issue Details

Issue description

Running evaluator label throws an error that the original tomogram is not a valid MRC file. This is despite the segementation file being accepted by the evaluator analyse command.

Expected behaviour

The original tomogram should pass the MRC file validation check.

Screenshots

n/a

Additional context

Certain files seem to be ok, so it may be a bad header in a specific file but needs more testing.

Reproducing Issue

Environment

• OS: MacOS 26.3.1 (25D2128)
• Python version: Python 3.14.3
• uv version: uv 0.10.11 (006b56b12 2026-03-16)

Steps to reproduce

1. Install the tool using the default installation method given in README.md.
2. Attempt to run evaluator label.