How can I convert a XLSB file to csv using python?

I've encountered this same problem and using pyxlsb does it for me:

from pyxlsb import open_workbook

with open_workbook('HugeDataFile.xlsb') as wb:
    for sheetname in wb.sheets:
        with wb.get_sheet(sheetname) as sheet:
            for row in sheet.rows():
                values = [r.v for r in row]  # retrieving content
                csv_line = ','.join(values)  # or do your thing

Most popular Excel python packages openpyxl and xlrd have no support for xlsb format (bug tracker entries: openpyxl, xlrd).

So I'm afraid there is no native python way =/. However, since you are using windows, it should be easy to script the task with external tools.

I would suggest taking look at Convert XLS to XLSB Programatically?. You mention python in title but the matter of the question does not imply you are strongly coupled to it, so you could go pure c# way.

If you feel really comfortable only with python one of the answers there suggests a command line tool under a fancy name of Convert-XLSB. You could script it as an external tool from python with subprocess.

I know this is not a good answer, but I don't think there is better/easier way as of now.