OK, that's my bad. I forgot that PyQt6 requires full enums. No shortcuts allowed. the line in question should actually read:
Code:
descargas = QStandardPaths.writableLocation(QStandardPaths.StandardLocation.DownloadLocation)
But something is still wrong. Once you click the OK button, Calibre closes and immediately complains that the installer is not valid. The calibre-setup.msi file HAS been created in Downloads, but it's only 3Kb in size. I think the "https://download.calibre-ebook.com/64bit" url is being redirected to an actual filename that urllib.request is not following. The urls for the other platforms actually end in file names.