Hi Tubbelubbe ,
You're right, that should be the problem with your export.
A CSV file is a text file, and CSV means Comma Separated Values, then the standard CSV has commas to separate the distinct values, and a double quote for text delimiters (or anything else containing a comma).
At this moment, ATUM Export only is compatible with the standard CSV format, we have in our TO-DO list to add the possibility to change the delimiters and separators. Meanwhile, I'm gonna try to explain why this is happening to you with your CSVs, and also what other possibilities you have.
I'm going to assume that your Mac is configured in Swedish.
As your language uses the "comma" as the decimal separator (although WordPress stores numbers with a point as the decimal separator), in order to prevent possible errors, Apple (and Microsoft with Windows too) changes the standard comma with a semicolon in your language and don't let to change it (we tried to do so in Microsoft Excel for Mac and Numbers).
In Excel for Windows, you can change the separator following this link instructions.
As far as I know, Open Office allows you to export CSV as you want in all its versions.
Anyway, we recommend using Google Sheets, as it allows you to set all the options you need when exporting to CSV.
Hope this helps,
José Andrés