There are three possible causes for this:
- Not enough time was allowed for the PDF to complete. When the PDF is being created, a green status bar moves across the bottom right of the screen. Do not click anything or type while this status bar is moving. You will know the PDF is complete when you can type again.
- The file name has special characters -- remove all non-Latin, non-alphanumeric characters from it.
- The folder to which the PDF is being saved has special characters in the name -- remove all non-Latin, non-alphanumeric characters from the folder name.
Start by ensuring that the PDF export is complete and if you are still getting a 0-byte file, check the file name and the folder name and adjust it if necessary.