versions 3.1.0 and up fail to open files saved with active filters.
When executing the below code on the same set of files, 3.1.2 gives "incorrect XML" errors on some of them, while 3.0.10 seems to work just fine.
def extract_sheet_name(cur_file):
wb = load_workbook(cur_file)
sheet_name = wb.active.title
return sheet_name