Windows – What’s the difference between – CSV (MS-Dos), CSV (Macintosh), CSV (comma delimited)

Those files are distributed? downloaded? Locally generated?

I think the unique way to solve your issue without access to the user's PC and without him to have to do something different of "double-click" on the file is to convert the files to .xls before distibuting or placing to download or to generate a .xls (or another format that works) instead of a .csv file. You can do that with a script or manually with a working Excel, depending on the number of files and the way they are generated.

While opening CSV files, Excel will use a system regional setting called List separator to determine which default delimiter to use.

Microsoft Excel will open .csv files, but depending on the system's regional settings, it may expect a semicolon as a separator instead of a comma, since in some languages the comma is used as the decimal separator. (from Wikipedia)

On Windows, you can change the List separator setting in the Regional and Language Options as specified on the Office support website :

Change the separator in a CSV text file

2. Click the Windows Start menu.
3. Click Control Panel.
4. Open the Regional and Language Options dialog box.
5. Click the Regional Options Tab.
6. Click Customize / Additional settings (Win10).
7. Type a new separator in the List separator box.
8. Click OK twice.

Note: this only works if the Decimal symbol is not also designated as comma (in line with the Wikipedia citation above). If it is, Excel will not use comma as the List separator, even if chosen. For many non-United States regions, comma is the default Decimal symbol.

On Mac OS X, this setting seems to be deduced from the decimal separator setting (in the Language & Region pane of System Preferences, go to Advanced). If the Decimal Separator is a point then the default CSV separator will be a comma, but if the Decimal Separator is a comma, then the default CSV separator will be a semicolon.

As you said yourself in the comment, there is an alternative for Mac users to quickly look at those CSV files. It's plugin for Quick Look called quicklook-csv that handles separator detection.