Hi @LarsJuhl ,
Perhaps you could use the List files in folder to get the files in the specified folder and then copy them to SharePoint.
Unfortunately, this action can only get the files in the specified folder, and can't get the files in the subfolder. This is a known limitation. MS Flow does not currently support such a feature.
If you want to get the files in the subfolder, you need to create a similar Flow and specify the Folder of the List files in folder action as a subfolder.
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Best Regards,