1M is xlsx file format limitation, and Excel on Mac can work with 1M just fine. But Excel is spreadsheet and not a database, so if you use it for so big dataset

1M is xlsx file format limitation, and Excel on Mac can work with 1M just fine. But Excel is spreadsheet and not a database, so if you use it for so big datasets (anything over 1000 rows or so) you are very probably just using plain wrong tool.