When I double-click on a .csv file, it is opened in Excel. The csv-files have columns delimited with semicolons (not commas, but also a valid format).

Using a German Windows/Excel setup, the opened file is displayed correctly, the columns are separated where the semicolons existed in the csv-file. But when I do the same on an (US-) English Windows/Excel setup, only one column is imported, showing the whole data including the semicolons in the first column.

You can change the CSV separator in Matukio>configuration>setting>advanced>CSV Separator BUT this does not change the system fields 'Booking number';'Event title';'Booked places' which still have ; (semi colons).

Workaround -
1. Rename the file .txt and import into Excel
2. Add this on the first line of the CSV file: sep=; or sep=, This will override system setting ("list separator character" and Excel will open the file correctly.

Most users will not know or want to do this, making CSV files useless for US customers.