Hi @Oskar Ex
Welcome to our forum!
Based on my research, i import the .csv file by going to File>Open&Export, Import/Export>Import from another program or file, Next>Comma Separated Values, Next>Locate the file where you saved, Next>Choose calendar(Foleder), Next>tick the box, drag and drop the corresponding options from the left to the right, and then i can import them normally.
You might want to take a look at my actions for some inspiration. More information: Import contacts from an Excel spreadsheet to Outlook - Microsoft Support (Just replace the Contacts folder with the Calendar folder). Hope it helps!
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