Suddenly your Excel CSV’s are now semicolon not comma. You can change this back to be a comma or else you can learn how to use semi colons instead of commas for CSV’s.
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Changing CSV’s back from semi colon to comma
In all likelihood this has happened when you are working on a new computer and it is a setting, not in Excel, but Windows.
So in Windows, search for the ‘Clock and Region’ settings, then
- Choose the ‘Change date, time or number formats’ option
- On the next screen choose ‘Additional Settings’, and
- in the ‘Customize Format’ screen, check what is listed as the ‘List Separator’. This will be what Excel uses as the delimiter so if you need to change it, you can do it here.

So now you won’t have a CSV using semicolon instead of a comma. You can use the same process if you actually want your ‘Comma Separated Files’ to rather be ‘semi colon separated’ files.
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Excel formulas need a semicolon instead of a comma?