I’m trying to read an xls file into a DataFrame in Python. The file is made available online by a Spanish electrical distribution grid operator on their website: https://www.ufd.es/wp-content/uploads/2024/05/publicacion-capacidad-Junio.xls There must be something fishy about this file, because it’s not only Python that has problems reading it: Numbers on Mac says the file format is invalid, however Excel under Windows has no problems opening the file (no errors or warnings reported). Google Sheets also opens the file without issues.