[IIsi50MHz]

…?

I must be misunderstanding you.

I can't get ISO-8601 dates to work properly in Excel unless I set my Windows to Australia locale, or make my own parser or use a third-party library.

Sure, I can format a field^Wcell with a custom format string, but Excel still won't believe me when I type/paste/import ISO-8601 dates. Unless I set 'Australia' systemwide.

And no, simply adding English (Australia) as one of the additional system languages, or keyboard layouts (and switching to that layout), or number+date+currency formats doesn't work.

[gsich]

Oh, works here. I set locale format to German (Germany) or (Austria) while using Windows with English language. All date/time/currency formats are sane.

But you could also customize the region settings in "Additional settings...".

[IIsi50MHz]

Good to know there are other countries with sane defaults. (-: