It's even worse than that. Office on my work computer is set to the English language, but my locale is French and so is my Windows language. It's saving semicolon-separated CSV files with the comma as a decimal point.

I need to uncheck File > Option Advanced > Use system separators and set the decimal separator to a dot to get Excel to generate English-style CSV files with semicolon-separated values. I can't be bothered to find out where Microsoft moved the CSV export dialog again in the latest version of Office to get it to spit out comma-separated fields.

Point is, CSV is a term for a bunch of loosely-related formats that depends among other things on the locale. In other words, it's a mess. Any sane file format either mandates a canonical textual representation for numbers independent of locale (like JSON) or uses binary (like BSON).

> It's saving semicolon-separated CSV files with the comma as a decimal point.

It's not though, is what I'm saying. It's saving semicolon-separated files, not CSV files. CSV files have commas separating the values. Saying that Excel saves "semicolon-separated CSV files" is nonsensical.

I can save binary data in a .txt file, that doesn't make it a "text file with binary data"; it's a binary file with a stupid name.

Sorry, but what Excel does is save to a file with a CSV extension. This format is well defined and includes ways to specify encoding and separator to be readable under different locales.

This format is not comma separated values. But Excel calls it CSV.

The headaches comes if people assume that a csv file must be comma separated.

I don't care what Excel calls it. As I said, if I name a file .txt but stuff it with binary data, it's not a text file.

That, bad specs, weird management/ timezone/ governance/ communications and random \n\r issues transformed a 2 day fun little project into a 4 week hell. I will never work with CSV in France ever again. Mostly because of Excel, normal CSV nice.